Medical device including an air evacuation system

ABSTRACT

Medical device assemblies capable of aspirating liquid into a syringe barrel or other medical devices while evacuating any air from the syringe are described. An exemplary medical device includes a syringe barrel, plunger rod and stopper assembly having an air permeable and liquid impermeable porous portion and structure for forming a vacuum within either the stopper or the plunger rod. Described is a medical device including a syringe barrel, plunger rod and stopper assembly having an air permeable and liquid impermeable porous portion and structure for forming a vacuum within chamber between the stopper and plunger rod wherein the plunger rod includes a sealing edge and is moveable relative to the stopper. Exemplary medical devices may include a vent for allowing air that permeates through the porous portion to escape to atmosphere. Methods for aspirating a syringe barrel with a liquid are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority from U.S. ProvisionalApplication No. 61/313,917, filed Mar. 15, 2010, the disclosure of whichis hereby incorporated in its entirety by reference thereto.

TECHNICAL FIELD

Aspects of the present invention relate to medical devices for use withcontainers capable of evacuating air trapped within the container whilefilling the container with liquid.

BACKGROUND

Syringe barrels contain, store, transfer and measure liquids, typicallycontaining medicaments or other fluids for delivery to a patient.Medical devices, including plunger rods and stoppers, are used toaspirate and expel liquid from syringe barrels. During aspiration, aircan become trapped within the syringe barrel. The presence of air withinthe syringe barrel can result in inaccurate dosage measurements andother issues.

Typically, air is removed from syringe barrels, by inverting the syringebarrel to force the air trapped within the barrel to the opening throughwhich the fluid is aspirated. The air is then expelled through theopening by applying a force on the plunger rod in the distal direction.This expulsion process, however, can result in the expulsion of aportion of the liquid aspirated into the syringe barrel. In addition,this method of removing air from the syringe barrel may require the userto agitate the barrel of the syringe to force the air bubbles to movetoward the opening.

Attempts to remove air from syringe barrels have included the use of aventing system to allow air to flow out of syringe barrels and othercontainers. Filters have been utilized to allow air to escape butprevent the desired liquid from also flowing out of the chamber of thebarrel. Such attempts, however, rely on natural forces to passivelycause a pressure differential across the filter to force air to permeatethrough the filter. In some instances, the filtering devices are part ofa separate component that must be attached to the tip of syringes by theuser prior to use of the syringe. There is a need to alleviate the needfor users to actively remove air from syringe barrels and othercontainers before use.

SUMMARY

In this disclosure, a convention is followed wherein the distal end ofthe device is the end closest to a patient and the proximal end of thedevice is the end away from the patient and closest to a practitioner.

Several aspects of a medical device including structure to evacuate airfrom a syringe barrel or other container when aspirating liquid into thesyringe barrel or container are provided. Exemplary syringe barrelsdescribed herein include a side wall having an inside surface defining achamber for retaining fluid, an open proximal end and a distal endincluding a distal wall with a tip extending distally therefrom havingan open passageway in fluid communication with said chamber. The medicaldevices include a plunger rod and stopper assembly disposed within thechamber of the syringe barrels or other containers.

In accordance with one or more embodiments, a medical device for usewith a syringe barrel is provided and includes a plunger rod disposedwithin the chamber of the syringe barrel and moveable in the proximaland distal direction within the chamber, a stopper assembly disposedwithin the chamber of the syringe barrel and moveable in the proximaland distal direction within the chamber, the stopper assembly forming afluid-tight seal with the inside surface of the syringe barrel, thestopper having a distal face, a proximal end and a body extending fromthe distal face to the proximal end defining a stopper cavity, means forcreating a vacuum within the stopper cavity; and means for permittingair to enter the stopper cavity and preventing liquid from entering thestopper cavity. In one or more embodiments, the medical device mayinclude means for venting the air within the stopper cavity that wasevacuated from the chamber. The vent may be associated with the stopperand/or plunger rod to release the evacuated air from the stopper cavity.The porous portion may include a selective barrier that defines a liquidpenetration pressure and an air penetration pressure that is less thanthe liquid penetration pressure. In one or more specific embodiments,the means for permitting air into the cavity and preventing liquid fromentering the cavity comprises a porous portion including one of ahydrophilic filter, a hydrophobic filter, a swellable polymer or acombination thereof.

In one or more embodiments, the plunger rod and stopper of one or moreembodiments are configured to create a pressure differential between thestopper cavity and a portion of the chamber extending from the distalwall and the distal face of the stopper assembly. The porous portion maybe associated with the stopper to permit air to flow into the stoppercavity and to prevent liquid from entering the stopper cavity. Thestructures and configurations of the plunger rod, stopper assembly andporous portion are described below with reference to various aspects.

In one or more embodiments of the present invention according to a firstaspect of the invention, the stopper is attached to the distal end ofthe plunger rod and includes an expandable portion that expands thestopper cavity to create a vacuum within the stopper cavity. Theexpandable portion may include a bendable wall, which may comprise anelastomeric material and has a spring constant that permits rapidexpansion of the bendable wall.

The stopper may also include a proximal end having an opening in fluidcommunication with the stopper cavity. The stopper also includes asealing portion disposed between the distal face of the stopper and theexpandable portion that forms a fluid-tight seal with the inside surfaceof the syringe barrel. In one or more embodiments, the sealing portionremains stationary despite an initial movement of the plunger rod in aproximal direction that causes the expandable portion to expand to drawair into the stopper cavity through the porous portion associated withthe stopper. The distal face of the stopper according to one or moreembodiments may be flexible and may flex concavely during movement ofthe plunger rod in a proximal direction and may flex convexly duringmovement of the plunger rod in the distal direction. In one or moreembodiments, the distal face may be convexly shaped to conform to thedistal wall of the barrel.

The distal end of embodiments of the plunger rod according to a firstaspect is disposed within the stopper cavity and forms a releasable sealwith the opening at the proximal end of the stopper and is proximallyand distally moveable within the stopper cavity. In one or moreembodiments, the distal end of the plunger rod includes a tapered neckshaped to form a releasable seal with the opening at the proximal end ofthe stopper, which may include an undercut that is shaped to receive thetapered neck of the plunger rod.

When the medical device according to a first aspect is assembled foruse, an initial movement of the plunger rod in a proximal directionrelative to the stopper forms the releasable seal between the distal endof the plunger rod and the opening, and the expandable portion expandsand draws air from the chamber into the stopper cavity through theporous portion disposed between the distal face and the stopper cavity.In one or more embodiments, movement of the plunger rod in a distaldirection relative to the stopper subsequent to the initial movement inthe proximal direction releases the releasable seal between the distalend of the plunger rod and the opening at the proximal end of thestopper. The release of the releasable seal allows the air within thestopper cavity to escape through the opening at the proximal end of thestopper.

In one or more embodiments according to a first aspect, the expandableportion of the stopper is configured to permit movement of the plungerrod relative to the stopper in a distal and a proximal direction. In aspecific embodiment, the expandable portion of the stopper is configuredso that upon a continuous movement of the plunger rod relative to thestopper in a distal direction, the distal end of the plunger rod blocksthe porous portion and prevents air from exiting the stopper cavitythrough the porous portion.

One or more embodiments according to a second aspect of the presentinvention also utilize a stopper that is attached to the distal end ofthe plunger rod and includes an expandable portion that expands thestopper cavity to create a vacuum within the stopper cavity and theproximal end of the stopper includes an opening in fluid communicationwith the stopper cavity. According to the second aspect, the expandableportion includes a pump body having a distal end attached to theproximal end of the stopper and includes a proximal end defining aplunger-engaging portion attached to the proximal end of the plungerrod. The pump body according to one or more embodiments includes a wallthat defines a pump cavity in fluid communication with the stoppercavity. In one or more embodiments, the wall may include a corrugatedwall formed from an elastomeric material and has a spring constant thatpermits expansion of the corrugated wall. The pump body is configured sothat upon application of an initial force on the plunger rod in thedistal direction relative to the stopper causes the pump body tocompress and a release of the initial force on the plunger rod in thedistal direction allows the pump body to expand and draw air from thechamber into the stopper cavity through the porous portion disposedbetween the distal face and the stopper cavity. In one or moreembodiments, the stopper may include a sealing portion disposed betweenthe distal face and the expandable portion that forms a fluid-tight sealwith the inside surface of the syringe barrel. During expansion of thepump body, the sealing portion remains stationary.

In one or more embodiments according to a second aspect of the presentinvention, the pump body may include a valve and a valve openingdisposed at the proximal end of the pump body in fluid communicationwith the pump cavity. The valve may be configured to open uponapplication of a force in the distal direction on the plunger rod andclose upon release of the force in the distal direction on the plungerrod.

In one or more embodiments according to a third aspect of the presentinvention, the distal end of the plunger rod includes an opening coveredby a pierceable wall and a plunger rod cavity including a vacuum and thestopper includes a stopper hub with a hollow spike extending from theproximal end in fluid communication with the stopper cavity for piercingthe pierceable wall of the plunger rod. The stopper hub may include anopen distal end and an open proximal end in fluid communication with thestopper cavity, the proximal end including a plunger-engaging portion toengage the distal end of the plunger rod. When assembled and in use, theproximal end of the stopper hub and the distal end of the plunger rodare configured to be positioned in a first position so that the hollowspike is disposed at a distance from the pierceable wall. In addition,the proximal end of the stopper hub and the distal end of the plungerrod are configured to engage in a second position so that the hollowspike pierces the pierceable wall and the vacuum draws air from thechamber into the stopper cavity through the porous portion disposedbetween the distal face and the stopper cavity.

In one or more embodiments of the medical device according to a fourthaspect, the stopper assembly includes an opening in the distal face influid communication with the stopper cavity and a plug extendingpartially through the opening and capable of forming a fluid-tight sealwith the opening. The plug includes a distal end, a proximal end, a headdisposed at the proximal end and an elongate core extending from thehead to the distal end, the elongate core including a channel extendingfrom the head to a distance from the distal end and extending partiallythrough the opening such that a portion of the channel is disposeddistally adjacent the opening to permit fluid communication between theopening and the stopper cavity and the head is disposed proximallyadjacent the opening.

In one or more embodiments according to a fourth aspect, the porousportion is formed from a swellable polymer and is disposed adjacent tothe plug. The porous portion forms an expandable barrier between thehead of the plug and the opening. Upon contact with a liquid, the porousportion expands and applies a force on the head in a proximal directionthat causes the channel to be positioned proximally adjacent the openingand allows the elongate core to form a fluid-tight seal with theopening, preventing fluid communication between the opening and thestopper cavity.

The plunger rod according to one or more embodiments of a fourth aspectof the present invention may include a sealing portion for forming afluid-tight seal with the interior surface of the barrel and is moveablewithin the chamber in the proximal and distal directions independentlyfrom the stopper assembly. In such embodiments, upon application of aforce on the plunger rod in the proximal direction, the plunger rodmoves in the proximal direction and creates a vacuum within the stoppercavity that draws air from the chamber through the channel of the pluginto the stopper cavity. In one or more embodiments, contact between theliquid and the porous portion causes the porous portion to expand andapply a force on the head in a proximal direction that causes thechannel to be positioned proximally adjacent the opening and preventsfluid communication between the opening and the stopper cavity. Theapplication of a force on the plunger rod in a distal direction causesthe plunger rod to engage the stopper and causes the plunger rod andstopper to move in the distal direction to expel the liquid drawn intothe chamber through the tip and opening.

In one or more specific embodiments according to a fourth aspect, thestopper and the plunger rod may be disposed at a pre-determined distancefrom the distal wall of the syringe barrel to permit use of the medicaldevice to administer a fixed-dose of liquid. In such embodiments, uponapplication of a force on the plunger rod in a proximal direction, thestopper remains stationary at a distance from the distal wall of thesyringe barrel, and a liquid and air are drawn into the chamber by thevacuum created within the chamber by sealing portion of the plunger rodand movement of the plunger rod in the proximal direction relative tothe stopper. The air drawn into the chamber by the vacuum is evacuatedthrough the channel of the plug into the stopper cavity and, uponcontact with the liquid, the porous portion expands and applies a forceon the head in a proximal direction that causes the channel to bepositioned proximally adjacent the opening and prevents fluidcommunication between the opening and the stopper cavity. Thereafter,application of a force on the plunger rod in a distal direction causesthe plunger rod to engage the stopper and causes the plunger rod andstopper to move in the distal direction to expel the liquid drawn intothe chamber through the tip and opening.

In one or more embodiments according to a fifth aspect, the distal faceof the stopper comprises an opening in fluid communication with thestopper cavity and the stopper comprises a duct assembly extendingpartially through the opening and capable of sealing the opening. Insuch embodiments, the porous portion is formed from a swellable polymerand is disposed adjacent to the duct assembly, which comprises distalend, a proximal end, a base disposed at the proximal end and a ductmember extending from the base to the distal end. The porous portion ispositioned to form expandable barrier between the base and the openingof the stopper. The duct member may include a tubular wall having anopen distal end and a lateral opening permitting fluid communicationbetween the open distal end and the stopper cavity. In one or moreembodiments, the lateral opening of the duct member extends from thebase to a distance between the open distal end and the base. In one ormore embodiments, the duct member extends partially through the openingof the stopper such that the open distal end is disposed distallyadjacent the opening to permit fluid communication between the openingand the stopper cavity and the base is disposed proximally adjacent theopening. When assembled and in use, upon contact with a liquid, theporous portion expands and applies a force on the base in a proximaldirection that causes the open distal end of the duct member to bepositioned proximally adjacent the opening and prevents fluidcommunication between the opening and the stopper cavity.

In one or more specific embodiments according to a fifth aspect, theplunger rod includes a sealing portion for forming a fluid-tight sealwith the interior surface of the barrel and is moveable within thechamber in the proximal and distal directions independently from thestopper assembly. In such embodiments, upon application of a force on aplunger rod in a proximal direction, the plunger rod moves in theproximal direction and creates a vacuum within the stopper cavity thatdraws air from the chamber into the stopper cavity through the opendistal end and lateral opening of the duct member. Upon contact with theliquid, the porous portion expands and applies a force on the base in aproximal direction that causes the channel to be positioned proximallyadjacent to the opening of the stopper and prevents fluid communicationbetween the opening of the stopper and the stopper cavity. The plungerrod may be attached to the stopper via a plunger engaging means disposedon the stopper and the application of a force on the plunger rod in thedistal direction that causes the plunger rod to engage the stopper.After engagement of the plunger rod and the stopper, the application ofa force on a plunger rod in the proximal direction causes the plungerrod and stopper to move in the proximal direction and draws liquid intothe chamber and application of a force on the plunger rod in the distaldirection causes the plunger rod and stopper to move in the distaldirection to expel the liquid drawn into the chamber.

One or more embodiments according to a sixth aspect of the presentinvention includes a stopper having a distal face with an opening influid communication with the stopper cavity, an opening at the proximalend of the stopper assembly in fluid communication with the stoppercavity and a stopper hub defining a hub cavity attached to the proximalend of the stopper. In one or more embodiments, the stopper hub includesan open distal end and an open proximal end in fluid communication withthe stopper cavity. The distal end of the plunger rod forms a fluidtight seal with the stopper hub and is slidably engaged with the stopperhub to move in a proximal direction relative within the hub cavity toform a vacuum within the hub cavity. The open proximal end of thestopper hub may include a peripheral wall and the distal end of plungerrod comprises a disc member forming a fluid-tight seal with theperipheral wall. The peripheral wall of one or more embodiments includesmeans for preventing distal movement of the plunger rod relative to thestopper hub, after an initial proximal movement of the plunger rodrelative to the stopper hub. In one or more specific embodiments, theperipheral wall of the stopper hub may include a vent in fluidcommunication with the chamber and the exterior of the medical device.The vent allows the air evacuated from the chamber of the syringe barrelinto the stopper cavity to escape.

When one or more embodiments according to a sixth aspect are assembledand in use, application of an initial force on the plunger rod in aproximal direction expands the hub cavity and creates a vacuum withinthe hub cavity that draws air from the chamber into the stopper cavitythrough the porous portion disposed between the distal face and stoppercavity. The application of a continuous force on the plunger rod in aproximal direction causes the plunger rod and stopper to move in aproximal direction and draws liquid into the chamber. In one or moreembodiments, the application of a force on the plunger rod in the distaldirection causes the plunger rod and stopper to move in the distaldirection and the stopper hub to remain expanded.

In one or more embodiments of the present invention according to aseventh aspect, the stopper assembly includes an opening in fluidcommunication with the stopper cavity and the proximal end of thestopper assembly is attached to the plunger rod. The plunger rodaccording to one or more embodiments has a nested configuration andincludes a body including a distal end, an open proximal end and aninside surface extending the stopper cavity from the distal face to theopen proximal end of the plunger rod, and a second plunger rod piece isdisposed within the stopper cavity and moveable in the proximal anddistal direction within the stopper cavity. The second plunger rod pieceincludes a sealing edge forming a fluid-tight seal with the insidesurface of the body of the plunger rod.

In one or more embodiments, the body comprises a retainer forrestricting movement of the second plunger rod piece within the stoppercavity after an initial movement of the second plunger rod piece in aproximal direction relative to the body. When assembled and in use, uponthe initial movement of the second plunger rod piece in a proximaldirection, a vacuum is created within the stopper cavity drawing airfrom the chamber into the stopper cavity through the porous portiondisposed between the distal face and the stopper cavity. Uponapplication of a force on the body in a proximal direction draws liquidinto the chamber and application of a force on the body in the distaldirection expels the liquid drawn into the chamber.

The seventh aspect of the present invention also includes a two-pieceplunger rod assembly. In one or more embodiments, the medical deviceincludes a syringe barrel as otherwise described herein, and a plungerrod assembly disposed within the chamber moveable in the proximal anddistal direction within the chamber. The plunger rod assembly includes aproximal end, a distal end including a sealing edge for forming afluid-tight seal with the inside surface of the syringe barrel and abody extending from the proximal end to the distal end, the bodyincluding an inside surface defining a plunger rod cavity. The distalend of the plunger rod may include an opening in fluid communicationwith the plunger rod cavity. The plunger rod assembly also includes aslidable portion disposed within the plunger rod cavity and moveable inthe proximal and distal direction within the plunger rod cavity. Theslidable portion is configured or shaped to form a fluid-tight seal withthe inside surface of the plunger rod cavity. The plunger rod andslidable portion configured to create a pressure differential betweenthe plunger rod cavity and a portion of the chamber extending from thedistal wall and the sealing edge of the plunger rod. The medical devicealso includes a porous portion associated with the plunger rod to permitair to flow into the plunger cavity and to prevent liquid from enteringthe plunger rod cavity. The slidable portion may include a retainer forrestricting movement of the slidable portion within the plunger rodcavity after an initial movement of the slidable portion in a proximaldirection relative to the plunger rod.

In use, the initial movement of the slidable portion of the plunger rodassembly in a proximal direction creates a vacuum within the plunger rodcavity that draws air from the chamber into the plunger rod cavitythrough the porous portion. Upon application of a force on the plungerrod in a proximal direction, a vacuum is created in the chamber of thesyringe barrel that draws liquid into the chamber and the application ofa force on the plunger rod in the distal direction expels the liquiddrawn into the chamber.

In one or more embodiments according to an eighth aspect of the presentinvention, utilizes a plunger rod having vacuum therein and includes anopen distal end that is attached to the proximal end of the stopperassembly. In one or more embodiments, the distal end of the plunger rodincludes a sidewall support defining a hollow interior within which theporous portion is disposed. The plunger rod may optionally include asecond porous portion disposed within the hollow interior of the plungerrod. The distal face of the stopper assembly forms a pierceable sealwith the stopper cavity and is pierceable to release the vacuum withinthe plunger rod. A needle disposed within the open passageway of thesyringe barrel and extends distally from the open passageway andproximally into the chamber of the syringe barrel. The needle includesan open distal end, an open proximal end including a piercing point forpiercing the distal face of the stopper assembly, a vent disposedadjacent to the proximal end in fluid communication with the open distalend and the open proximal end of the needle.

When assembled and in use, the plunger rod and stopper are disposedwithin the chamber such that the piercing point does not penetrate thedistal face and the vacuum within the plunger rod remains intact. Uponan application of an initial force on the plunger rod in the distaldirection, the piercing point pierces the distal face and releases thevacuum that draws air from the chamber into the stopper cavity. Uponapplication of a force on the plunger rod in a proximal direction, thedistal face forms a fluid tight seal with the stopper cavity andprevents liquid from entering the stopper cavity as the liquid is drawninto the chamber.

One or more embodiments according to a ninth aspect pertain to a methodfor filling a syringe barrel with liquid. In one or more embodiments,the method includes providing a syringe barrel having a chamber havingan air source, a needle cannula having an opening, a plunger rodassembly including a sealing means for forming a fluid tight seal withthe syringe barrel, and means for evacuating an air from the chamberinto the plunger rod assembly, submerging the opening of the needlecannula in a liquid, providing a vacuum within the plunger rod assembly,drawing the air source and the liquid into the chamber and evacuatingthe air source from the chamber into the plunger rod assembly. Themethod may optionally include venting the air from the plunger rodassembly. In one or more specific embodiments, the step of providing avacuum within the plunger rod assembly comprises expanding a cavitywithin the plunger rod assembly. The step of submerging the opening ofthe needle cannula in one or more embodiments occurs after providing avacuum within the plunger rod assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of a medical device including anassembled syringe and plunger rod;

FIG. 2 illustrates a disassembled view of the medical device of FIG. 1;

FIG. 3A shows a side elevational view of the stopper illustrated inFIGS. 1 and 2 in a compressed state;

FIG. 3B shows a side elevational view of the a according to analternative embodiment in a compressed state;

FIG. 4 illustrates a cross-sectional view of the stopper shown in FIG. 3taken along line 4-4;

FIG. 5 illustrates a perspective cross-sectional view of the stoppershown in FIG. 4;

FIG. 6 illustrates a side elevational view of the stopper shown in FIG.3A in an expanded state;

FIG. 7 illustrates a perspective cross-sectional view of the stoppershown in FIG. 6 taken along line 7-7;

FIG. 8 illustrates a cross-sectional view of the medical device of FIG.1 taken along line 8-8;

FIG. 9 illustrates a cross-sectional view of the medical device shown inFIG. 8 positioned to draw liquid from a vial after application of aninitial force to the plunger rod in the proximal direction;

FIG. 9A is an enlarged partial view of the stopper and stopper-engagingportion shown in FIG. 9;

FIG. 10 shows the medical device shown in FIG. 9 drawing liquid from thevial into the syringe barrel upon application of a continuous force tothe plunger rod in the proximal direction;

FIG. 11 illustrates the medical device shown in FIG. 10 after air isevacuated from the syringe barrel into the stopper cavity and as thecontinuous force is applied to the plunger rod in the proximaldirection;

FIG. 12 illustrates air being evacuated from the cavity of the stoppershown in FIG. 11 upon application of an initial force to the plunger rodin the distal direction;

FIG. 13 illustrates the expulsion of the liquid from the syringe barrelupon application of a continuous force to the plunger rod in the distaldirection;

FIG. 14 illustrates a disassembled view of a syringe according to asecond aspect of the present invention;

FIG. 15 illustrates an enlarged partial view of the stopper assemblyshown in FIG. 14;

FIG. 16 shows a perspective cross-sectional view of the stopper assemblyand a distal end of the plunger rod shown in FIG. 14 taken along line16A-16A;

FIG. 17 shows a cross-sectional view of the assembled medical deviceillustrated in FIG. 14 taken along line 17-17;

FIG. 18 shows a cross-sectional view of the assembled medical deviceshown in FIG. 17 upon application of an initial force in the distaldirection on the plunger rod;

FIG. 19 shows an enlarged partial view of the distal end of the syringeshown in FIG. 18;

FIG. 20 illustrates a cross-sectional view of medical device shown inFIG. 19 positioned to draw liquid from a vial after application of aninitial force to the plunger rod in the proximal direction;

FIG. 21 is an enlarged partial view of the air being evacuated from thecavity of the stopper shown in FIG. 20;

FIG. 22 shows a cross-sectional view of the medical device shown in FIG.21 drawing liquid from the vial into the syringe barrel upon applicationof a continuous force to the plunger rod in the proximal direction;

FIG. 23A illustrates a cross-sectional view of the medical device shownin FIG. 21A filled with liquid from the vial prior to the expulsion ofthe liquid from the syringe barrel upon application of a continuousforce to the plunger rod in the distal direction;

FIG. 23B illustrates an enlarged partial view of the medical deviceshown in FIG. 23A;

FIG. 24 illustrates a cross-sectional view of the medical device shownin FIG. 23 upon application of an initial force to the plunger rod inthe distal direction;

FIG. 25 shows a cross-sectional view of the medical device shown in FIG.24 after expulsion of the liquid from the syringe barrel uponapplication of a continuous force to the plunger rod in the distaldirection;

FIG. 26 illustrates a disassembled view of a syringe barrel and one ormore embodiments of a medical device according to a third aspect of thepresent invention;

FIG. 27 illustrates an enlarged partial view of the stopper assemblyshown in FIG. 26;

FIG. 28 illustrates a perspective cross-sectional view of the stopperassembly and the plunger rod shown in FIG. 26 taken along line 28-28;

FIG. 29A illustrates a cross-sectional view of the assembled medicaldevice illustrated in FIG. 26 taken along line 29A-29A;

FIG. 29B illustrates an enlarged partial view of the medical deviceillustrated in FIG. 29A;

FIG. 30 illustrates a cross-sectional view of the medical device shownin FIG. 29A positioned to draw liquid from a vial after application ofan initial force to the plunger rod in the distal direction;

FIG. 31 illustrates an enlarged partial view of the stopper, plunger rodand syringe barrel shown in FIG. 30;

FIG. 32 shows a cross-sectional view of the medical device shown in FIG.31 drawing liquid from the vial into the syringe barrel upon applicationof a continuous force to the plunger rod in the proximal direction;

FIG. 33 illustrates an enlarged partial view of the air being evacuatedfrom the cavity of the stopper shown in FIG. 32;

FIG. 34 illustrates a cross-sectional view of the medical device shownin FIG. 32 filled with liquid from the vial prior to the expulsion ofthe liquid from the syringe barrel upon application of a continuousforce to the plunger rod in the distal direction;

FIG. 35 illustrates a disassembled view of a syringe barrel, needle huband one or more embodiments of a medical device according to a fourthaspect of the present invention;

FIG. 36 illustrates an enlarged partial view of the stopper assemblyshown in FIG. 35;

FIG. 37 illustrates a cross-sectional view of the assembled medicaldevice illustrated in FIG. 35;

FIG. 38 illustrates a cross-sectional view of the medical device shownin FIG. 37 upon application of an initial force to the plunger rod inthe proximal direction;

FIG. 39 illustrates the medical device shown in FIG. 38 upon applicationof a force to the plunger rod in the distal direction to attach theplunger rod and stopper;

FIG. 40 illustrates the medical device shown in FIG. 39 drawing adesired amount of liquid from a vial into the syringe upon applicationof a force in the proximal direction to the attached plunger rod andstopper;

FIG. 41 illustrates the medical device shown in FIG. 40 after expulsionof the liquid from the syringe barrel upon application of a continuousforce to the plunger rod in the distal direction

FIG. 42 shows a cross-sectional view of the medical device illustratedin FIG. 35 assembled in a fixed-dose configuration;

FIG. 43 illustrates a cross-sectional view of the medical device shownin FIG. 42 drawing liquid from a vial into the syringe barrel afterapplication of a continuous force to the plunger rod in the proximaldirection;

FIG. 44 illustrates a cross-sectional view of the medical device shownin FIG. 43 filled with liquid from the vial;

FIG. 45 illustrates a cross-sectional view of the medical device shownin FIG. 44 after expulsion of the liquid from the syringe barrel uponapplication of a continuous force to the plunger rod in the distaldirection;

FIG. 46 shows a disassembled view of a syringe barrel and one or moreembodiments of a medical device according to a fifth aspect of thepresent invention;

FIG. 47 illustrates an enlarged partial view of the stopper assemblyshown in FIG. 46;

FIG. 48 illustrates a cross-sectional view of the assembled medicaldevice illustrated in FIG. 47 assembled with a syringe barrel takenalong line 48-48;

FIG. 49 illustrates an enlarged partial view of the medical device shownin FIG. 48;

FIG. 50 illustrates the medical device shown in FIG. 48 drawing liquidfrom a vial into the syringe barrel and upon application of an initialforce to the plunger rod in the proximal direction;

FIG. 51 illustrates an enlarged partial view of the medical device shownin FIG. 50;

FIG. 52 illustrates the medical device shown in FIG. 50 afterapplication of the initial force to the plunger rod in the proximaldirection;

FIG. 53 illustrates the medical device shown in FIG. 52 afterapplication of a force on the plunger rod in the distal direction;

FIG. 54 shows an enlarged partial view of the medical device shown inFIG. 53;

FIG. 55 illustrates the medical device shown in FIG. 53 filled withliquid from the vial;

FIG. 56 illustrates a disassembled view of a syringe barrel and one ormore embodiments of a medical device according to a sixth aspect of thepresent invention;

FIG. 57 illustrates an enlarged partial view of the stopper, stopper huband enlarged partial view of the plunger rod shown in FIG. 56;

FIG. 58A shows a perspective view of the filter shown in FIG. 57 priorto contact with a liquid;

FIG. 58B shows a perspective view of the filter shown in FIG. 57 aftercontact with a liquid;

FIG. 59 illustrates a perspective cross-sectional view of the filter andthe stopper shown in FIG. 57 in an assembled state taken along line59-59;

FIG. 60 shows a perspective cross-sectional view of the stopper hubshown in FIG. 57 taken along line 60-60 and an enlarged partial view ofthe plunger rod shown in FIG. 56;

FIG. 61 illustrates a cross-sectional view of the assembled medicaldevice illustrated in FIG. 56 taken along line 61-61;

FIG. 62 illustrates an enlarged partial view of the medical device shownin FIG. 61;

FIG. 63 illustrates the medical device shown in FIG. 61 drawing liquidfrom a vial into the syringe barrel after application of the initialforce to the plunger rod in the proximal direction;

FIG. 64 illustrates an enlarged partial view of the medical device andsyringe shown in FIG. 63;

FIG. 65 shows the medical device shown in FIG. 63 filled with liquidfrom the vial;

FIG. 66 shows an enlarged partial view of the medical device shown inFIG. 65;

FIG. 67 illustrates the medical device shown in FIG. 65 afterapplication of a continuous force on the plunger rod in the distaldirection to expel the fluid contained within the syringe barrel;

FIG. 68 illustrates a disassembled view of a syringe barrel and one ormore embodiments of a medical device according to a seventh aspect ofthe present invention;

FIG. 69 illustrates cross-sectional view of medical device shown in FIG.68 taken along line 69-69;

FIG. 70 shows a view of the medical device illustrated in FIG. 68assembled and positioned to draw liquid from a vial into the syringebarrel;

FIG. 71 illustrates an enlarged partial view of the medical device shownin FIG. 70;

FIG. 72 illustrates the medical device shown in FIG. 70 with the medicaldevice assembled in an extended state;

FIG. 73 shows an enlarged partial view of the medical device shown inFIG. 72;

FIG. 74 the medical device shown in FIG. 72 filled with liquid from thevial;

FIG. 75 shows an enlarged partial view of the medical device shown inFIG. 74;

FIG. 76 illustrates the medical device shown in FIG. 74 afterapplication of a continuous force on the medical device in the distaldirection to expel the fluid contained within the syringe barrel;

FIG. 77 illustrates a disassembled view of a syringe barrel and one ormore embodiments of a medical device according to a eighth aspect of thepresent invention;

FIG. 78 illustrates a cross-sectional view of the syringe barrel andmedical device shown in FIG. 77 taken along line 77-77;

FIG. 79 shows a perspective view of the needle shown in FIG. 78;

FIG. 80 illustrates a view of the medical device illustrated in FIG. 77assembled;

FIG. 81 illustrates an enlarged partial view of the medical device shownin FIG. 80;

FIG. 82 illustrates the medical device shown in FIG. 81 drawing liquidfrom a vial into the syringe barrel after application of the initialforce to the plunger rod in the distal direction;

FIG. 83 shows an enlarged partial view of the medical device and syringeshown in FIG. 82;

FIG. 84 shows the medical device shown in FIG. 82 filled with liquidfrom the vial; and

FIG. 85 illustrates the medical device shown in FIG. 84 afterapplication of a continuous force on the plunger rod in the distaldirection to expel the fluid contained within the syringe barrel.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the invention, it isto be understood that the invention is not limited to the details ofconstruction or process steps set forth in the following description.The invention is capable of other embodiments and of being practiced orbeing carried out in various ways. It is to be understood that theconfigurations shown in FIGS. 1-84 are merely exemplary, and thecomponents can be different in shape and size than shown.

The embodiments of the present invention described herein, with specificreference to various aspects, provides for a medical device includingsyringe barrel or other containers to draw liquid from a source into thesyringe barrel. The medical devices described herein generally include aplunger rod and stopper assembly and means to actively remove orevacuate air from the liquid drawn into the syringe barrel or othercontainer. The embodiments of the medical device may be used with othertypes of containers, in addition to syringe barrels, for example,needleless IV sets or other devices having a chamber that can be used tostore and/or transfer liquid medication and/and/or other liquids.Syringe barrels described herein may include optional needle hubs,integrated needle cannulas and/or needle shields.

Aspects of the present invention described herein incorporate amechanism that creates greater pressure differentials across a porousportion disposed or formed with one or more of the stopper, plunger rodand/or stopper-plunger rod assemblies described herein. Previousattempts to evacuate air from syringes have been largely limited toblood draw syringes and have relied on the pressure differential acrosshydrophobic filters, which is often referred to as a “bubble point” ofthe filter, i.e., the pressure to force air through the filter. In suchdevices, the pressure differential is largely created by the patient'sarterial and/or venous pressure. Varying the pore size and materialsused to form the hydrophobic filters have been attempted to solve theproblems posed by situations or applications that provide a low pressuredifferential across the porous portion.

In embodiments of the present invention, means for evacuating air fromsyringes have been incorporated which provide a greater pressuredifferential. For example, as shown in FIGS. 1-13, the medical device100 the stopper includes an expandable portion 162 that increases thepressure differential between the stopper cavity 166 of the stopper andthe chamber 118 of the syringe barrel and is not reliant on externalforces to create a pressure differential causing the air to permeatethrough the hydrophobic filter or porous portion 190. As will bedescribed in further detail below, the second aspect of the presentinvention, shown in FIGS. 14-22, the medical device 200 utilizes astopper hub 250 including a pump body 253 to create the increasedpressure differential across the porous portion. In the embodimentsaccording to the second aspect, a vacuum is created within the pump body253 as the user applies an initial force in the distal direction tocompress the pump body 253 and the pump body 253 springs back to anexpanded state as the initial force on an attached plunger rod 240 isreleased to create a vacuum within the pump body 253, which creates anincreased pressure differential across the porous portion. Embodimentsaccording to a third aspect of the present invention shown in FIGS.26-34, illustrate a medical device 300 including a plunger rod 340having a pre-formed vacuum within the plunger rod 340 and a stopper 360attached to the plunger rod and having a structure to release the vacuumwithin the plunger rod 340 into a cavity within the stopper 360, whichprovides a greater pressure differential across the porous portion. Theembodiments shown according to the fourth aspect in FIGS. 35-44 utilizea plunger rod 440 having a first stopper 447 and a separate secondstopper assembly 460 to form a vacuum between the plunger rod 440 andthe stopper assembly 460. Embodiments according to the fifth aspect ofthe present invention shown in FIGS. 45-54 also utilize a plunger rod540 having a sealing edge 547 and a separate stopper assembly 560 toform a vacuum within the chamber 518 of the syringe between the stopperassembly 560 and the plunger rod 540. Embodiments according to a sixthaspect of the invention shown in FIGS. 55-66 illustrate a plunger rod640 slidably engaged to a stopper 660 to create a vacuum within a cavity666 formed within the stopper 660. The embodiments according to aseventh aspect of the present invention utilize a two-piece plunger rodsystem that allows a user to move one plunger rod piece 750 relative tothe other plunger rod piece 730 to form a vacuum in a space or stoppercavity 734 formed between the plunger rod pieces. The embodimentsaccording to an eight aspect of the present invention utilize a stopper860 and plunger rod 840 having a pre-formed vacuum disposed therein thatmay be released by a needle 880 that permits air to escape into stopper860 and plunger rod 840 assembly. Accordingly, the medical devicesdescribed herein can be used in more applications, for example, theadministration of medication to a patient, measurement of liquids inlaboratory testing and the like regardless of the viscosity or otherproperties of the liquid.

The porous portion of the embodiments of the medical devices describedherein may include a selective barrier that defines a liquid penetrationpressure and an air penetration pressure that is less than the liquidpenetration pressure. In one or more embodiments, the porous portion mayinclude a hydrophilic filter, a hydrophobic filter, a swellable polymerand/or other suitable materials that are air permeable and liquidimpermeable and/or combinations thereof. Examples of suitablehydrophilic filters include hydrophilic polytetrafluoroethylene membranefilters. Such filters are available from the W.L. Gore & Associates ofElkton, Md. Examples of suitable hydrophobic filters include a materialknown under the trademark “Tyvek” produced by E.I. duPont de Nemours andCompany, Inc. of Wilmington, Del. which is a spunbonded olefin or amaterial known under the trademark “Acropor” that is made ofacrylonitrile polyvinyl chloride reinforced with nylon and may beobtained from Gelman Instrument Company or Ann Arbor, Mich. Othersuitable hydrophobic filters include filters made ofpolytetrafluoroethylene, nylon, cellulose nitrate, cellulose acetate,and polethersulfone.

Suitable hydrophobic filters resist liquid from wicking through thefilter at a reasonable pressure gradient. In one or more embodiments,the hydrophobic filter has a water penetration pressure, or the pressureat which water permeates or penetrates the hydrophobic filter that isgreater than the air penetration pressure, or the pressure at which airpermeates or penetrates the hydrophobic filter. In a specificembodiment, the water penetration pressure of the hydrophobic filter isgreater than the vacuum pressure generated within the chamber of thesyringe barrel or other containers and/or within the stopper and plungerrod assemblies described herein. This difference in pressure creates apressure differential across the porous portion that drives air andliquid toward the porous portion, with the liquid impermeable propertyof the porous portion preventing liquid from permeating through theporous portion and allowing air to permeate through the porous portion.

In accordance with one or more embodiments, the porous portion describedherein may include a swellable polymer comprising a plurality ofopenings or holes that allow fluid communication of air through theopenings. In one or more embodiments, the swellable polymer swells orexpands upon contact with a liquid, thereby closing the openings orholes of the swellable polymer. In one or more embodiments, theswellable polymers are activated or swell upon contact with liquids thatcontain water. In accordance with one or more alternative embodiments,the swellable polymers are activated or swell upon contact with liquids,regardless of the water content of the liquids. Accordingly, in suchembodiments, air contained within the syringe barrel is permitted toescape through the holes prior to contact between the swellable polymerand liquid. Upon contact with a liquid, the holes of the swellablepolymer close and no fluid is permitted to enter the holes or escapefrom the syringe barrel. Examples of swellable polymers includehydrogel-forming polymers. As used herein, hydrogels include materialsthat may be characterized as having chemical structures with an affinityfor aqueous solutions in which they swell rather than dissolve.Hydrogels may also be referred to as gelling material (AGM) orsuper-absorbent polymers (SAP). Exemplary swellable polymers may beproduced by initially polymerizing unsaturated carboxylic acids orderivatives thereof, such as acrylic acid, alkali metal (e.g., sodiumand/or potassium) or ammonium salts of acrylic acid, alkyl acrylates,and the like in the presence of relatively small amounts of di- orpoly-functional monomers such as N,N′-methylenebisacrylamide,trimethylolpropane triacrylate, ethylene glycol di(meth)acrylate, ortriallylamine. Other known swellable polymers may also be utilized.

Alternatively, the porous portion may be formed from a combination of ahydrophobic filter and a swellable polymer. For example, the center ofthe porous portion may be formed from a swellable polymer and theremaining portion of the porous portion which surrounds the swellablepolymer is formed from a hydrophobic filter, and/or vice versa. In oneor more embodiments, the porous portion may be provided the form of alaminate including a first layer formed from a hydrophobic filter and asecond layer formed from a swellable polymer. In one or more specificembodiments, the laminate porous portion may be positioned so thelayered hydrophobic filter is the distal most layer and, thus, is incontact with the liquid before the swellable polymer or vice versa.

Previous attempts to evacuate air from syringe barrels and othercontainers have utilized filters that could interfere with the sealingmechanism of the stopper and plunger assembly. The size of such filtersis often large enough to cover the distal face of the stopper and alsothe sealing portion that forms a seal with the syringe barrel. Thepresence of a filter between the sealing portion of the stopper and thesyringe barrel can interfere with the fluid-tight engagement between thestopper and syringe barrel and prevent the proper formation of thevacuum within the syringe barrel to aspirate fluid or liquid. The use ofa porous portion may be shaped and positioned to occupy a portion of thedistal face to provide an evacuation system for the air within thesyringe barrel to escape without interfering with the ability of thestopper or plunger rod to form a seal with the syringe barrel.

FIGS. 1-13 illustrate one of more embodiments of a medical device 100according to a first aspect of the invention. The medical device 100includes a plunger rod 140 attached to a stopper 160. For illustration,the medical device 100 is shown in use with a container in the form of asyringe barrel 110 with needle hub 180 in FIGS. 1-13. As shown moreclearly in FIGS. 2 and 8, the syringe barrel 110 includes an openproximal end 119 and a distal end 111 and a distal wall 112. A sidewall114 extends from the distal end 111 to the open proximal end 119 andincludes an interior surface 116 that defines a chamber 118 forretaining or holding fluids, which may include liquid medication and/orother liquids. The distal end 111 may also include a tip 120 having anopen passageway 122 therethrough in fluid communication with the chamber118. The barrel 110 may include an optional finger flange 124 at theopen proximal end 119 extending radially outwardly from the sidewall114. As shown in FIGS. 1-13, a needle hub 180 is utilized to attach theneedle cannula 184 to the tip 120. The needle hub 180 includes a needlecannula 184 with a lumen 186 or opening therethrough and may be attachedto the tip 120 so that the lumen 186 is in fluid communication with theopen passageway 122 and the chamber 118. As shown, the needle hub 180includes a distal end 181 and a proximal end 189 and a body 182 defininga hollow space 188. When assembled, the tip 120 is inserted into thehollow space 188 through the open proximal end 189 of the needle hub 180until the body 182 frictionally engages the tip 120. Alternatively, theneedle cannula 184 may be attached to the tip 120, without the use of aneedle hub, using other methods known in the art. The interior surface116 of the syringe barrel 110 may have a smooth surface that is free ofany protrusions or depressions. In addition, the body 182 of the needlehub 180 may also incorporate a smooth interior surface that is free ofany protrusions or depressions. In use, the plunger rod 140 and stopper160 are inserted into the open proximal end 119 of the syringe barrel110.

As more clearly shown in FIGS. 3-5, the stopper 160 includes a distalend 161 and a proximal end 169. The stopper 160 includes an expandableportion 162 adjacent to the proximal end 169, an outside surface 163 andan inside surface 164 defining a stopper cavity 166. The stopper 160further includes a sealing portion 168 formed adjacent to the distal end161. The stopper 160 may be formed from an elastomeric material,polymeric material or other material known in the art. The sealingportion 168 may be formed from an elastomeric material having greaterrigidity than the elastomeric material forming the expandable portion162. The expandable portion 162 may be formed from a compressibleelastomeric material, for example, a rubber material. The sealingportion 168 includes at least one peripheral seal 170 shaped to form afluid-tight seal with the interior surface 116 of a syringe barrel. Theembodiments shown in FIGS. 4-6 include two peripheral edges. In one ormore embodiments, the peripheral seal 170 may have a circularcross-section for forming a fluid-tight seal with a syringe barrelhaving an interior surface 116 with a circular cross-section. Thesealing portion 168 and/or peripheral seal 170 may be formed from amaterial suitable for forming a fluid-tight seal with the interiorsurface 116 of the syringe barrel and may include the same or differentmaterial utilized to form the stopper 160.

In use, the expandable portion 162 is utilized to create a vacuum withinthe stopper cavity 166 by operating as a positive displacement pump byexpanding the stopper cavity 166, which is sealed when the medicaldevice are positioned with the open lumen 186 of the needle cannula 184is submerged in the liquid to be aspirated into the syringe barrel 110.The pressure differential between the stopper cavity 166 and the chamber118 draws the air within the chamber 118 into the stopper cavity 166, aswill be discussed in greater detail below. To expand the stopper cavity166, the expandable portion 162 of the stopper 160 includes a bendablewall 172. In the embodiments shown in FIGS. 1-13, the bendable wall 172includes a single bend or corrugation. In a specific embodiment, thebendable wall 172 may include two or more bends or corrugations. Thevolume of the stopper cavity 166 expands and contracts as the length ofthe bendable wall 172 increases and decreases, respectively. Changes inthe length and/or cross-sectional width of the bendable wall 172 causethe expandable portion 162 to compress to a compressed state, as shownin FIGS. 3-5, and expand to an expanded state, as shown in FIGS. 6 and7. As shown in FIGS. 12 and 13, the length and/or cross-sectional widthof the bendable wall 172 may decrease as an initial force is applied tothe stopper 160 in the distal direction. This occurs, for example, whenthe plunger rod 140 and stopper 160 are assembled within the chamber 118of a syringe barrel 110 and an initial force is applied to the plungerrod 140 in the distal direction. The length and/or cross-sectional widthof the bendable wall 172 of one or more embodiments may increase as theplunger rod 140 exerts an initial force is applied to the stopper 160 inthe proximal direction, for example, during aspiration of a syringebarrel. Alternatively, the length and/or cross-sectional width of thebendable wall 172 may increase as the plunger rod 140 exerts an initialforce to the stopper 160 in the distal direction, for example, duringexpulsion of the liquid from the syringe barrel. The expansion of thelength of the bendable wall 172 is shown in FIGS. 8 and 9 and will bediscussed in greater detail below.

Alternatively, the bendable wall 172 resists compression afterexpansion. In one or more embodiments, the bendable wall 172 is moldedor formed to have a geometry that creates a spring-like effect orreaction to the application of forces in the distal and/or proximaldirection. The expandable portion 162 may be formed from an elastomericmaterial or other material that has a spring constant to expand andcompress during normal operation of the medical device 100 and syringebarrel 110. Specifically, in one or more embodiments, the expandableportion 162 has permits expansion so the user does not experience anysignificant tactile response to the expansion and/or is not required totake active steps to expand the stopper 160. In one or more embodiments,the spring constant of the expandable portion 162 may be modifieddepending on the application and the viscosity of the liquid to beaspirated into the syringe barrel 110. The stopper 160 may be providedand assembled with the plunger rod in a compressed state, as shown inFIG. 8. In one or more embodiments, the user may compress the stopperprior to assembly with the plunger rod 140 and the syringe barrel 110 orother container.

In the embodiments shown in FIGS. 3-5, the bendable wall 172 has asingle inward bend or single pinched area. The bendable wall 172 iscompacted inwardly to reduced length and/or cross-sectional width of theexpandable portion 162, reducing the size and/or volume of the stoppercavity 166. Expansion of the bendable wall 172 shown in FIGS. 3-5 isshown in FIGS. 6 and 7, where the single inward bend or single pinchedarea is expanded or released and the length and/or cross-sectional widthof the bendable wall 172 expands to expand the size and/or volume of thestopper cavity 166 from a compressed state to an expanded state. It willbe understood the bendable wall 172 may curve inwardly to reduce thelength and/or cross-sectional width of the expandable portion 162.Alternatively, the expandable portion 162 may include a collapsible wall(now shown) having more than one telescoping segment that reduce andexpand the length and/or cross-sectional width of the expandable portion162.

According to one or more embodiments, the length and/or cross-sectionalwidth of the expandable portion 162 of the stopper may be pre-definedfor specific applications. In one or more embodiments, the length and/orcross-sectional width of the expandable portion 162 may be sized to drawin a pre-defined amount of air trapped within a syringe barrel 110. In aspecific embodiment, the length and/or cross-sectional width of theexpandable portion 162 may be sized to draw in a pre-defined amount ofair trapped within the tip of a syringe. In a more specific embodiment,the volume of the stopper cavity 166 may be sized to hold a pre-definedamount of air trapped within a syringe barrel. In a specific embodiment,the volume of the stopper cavity 166 may be sized to hold a pre-definedamount of air trapped within the tip of a syringe.

The distal end 161 of the stopper 160 includes a distal face 174including an opening 171 and a porous portion 190 and the proximal end169 of the stopper 160 includes a proximal wall 176 having an aperture178 defined by a rim 179. The distal face 174 also includes a conduit175 in fluid communication with the stopper cavity 166 and the opening171. In one or more embodiments, the distal face 174 is flexible andflexes concavely and convexly, as will be described in greater detailwith reference to FIGS. 8-13. The distal face 174 may also be shapedconvexly so that it conforms more closely to the shape of the distalwall 112 of the syringe barrel 110 to expel as much liquid from thechamber 118 as possible. A porous portion 190 is disposed in the conduit175 and/or opening 171 and in fluid communication with the conduit 175,stopper cavity 166 and the opening 171. In one or more embodiments, theporous portion 190 is air permeable and liquid impermeable. In otherwords, the porous portion 190 forms a selective barrier that a liquidpenetration pressure and an air penetration pressure that is less thanthe liquid penetration pressure.

The porous portion 190 may have a circular shape. Alternatively, theporous portion 190 may have a square and/or rectangular shape. In oneembodiment, the porous portion 190 may be integrally formed or disposedon the distal face 174, adjacent to the opening 171. In a specificembodiment, the porous portion has a cross-sectional width that issmaller than the cross-sectional width of the distal face 174. Theporous portion may also be integrally formed and/or disposed adjacent tothe conduit 175 on the inside surface 164 of the stopper. In a specificembodiment, the porous portion 190 may have a cross-sectional with thatis smaller than the cross-sectional width of the inside surface 164 ofthe stopper.

The porous portion 190 can be integrally formed on the distal face 174and covers the opening 171, with the peripheral edges of the distal face174 and the sealing portion 168 remaining non-porous. In a specificembodiment, the porous portion 190 is separated from the sealing portion168 by the distal face 174. In a more specific embodiment, the porousportion 190 is separated from the sealing portion 168 by the peripheralseal 170.

The porous portion may also be shaped to fit within the opening 171 andform a fluid-tight engagement with the opening. For example, the porousportion may extend from the distal face 174 into the conduit 175. In oneor more embodiments, the porous portion 190 may have a periphery that ismolded to a portion of the distal face 174. In one or more embodiments,the porous portion 190 may be attached to the distal face 174 of thestopper by mechanical means, for example, adhesives and/or molding. In aspecific embodiment, the distal face 174 may include a pocket (notshown) for securing the porous portion 190 adjacent to the distal face174 and the opening 171.

The porous portion 190 may include a hydrophobic filter, swellablepolymer, other materials that are air permeable and liquid impermeableand/or combinations thereof, as described above.

Referring to FIGS. 1-13, the medical device 100 includes a structure forventing the air evacuated through the porous portion 190 from themedical device 100 and/or syringe barrel 110. The proximal wall 176 ofthe stopper 160 may include an undercut 173 adjacent the rim 179 thatdefines the aperture 178. In one or more embodiments, the aperture 178is sized and/or shaped to permit attachment of the plunger rod 140 tothe stopper 160. As shown, the undercut 173 is sized and shaped to forma releasable seal between the plunger rod 140 and stopper 160 andprevent fluid communication between the stopper cavity 166 and theaperture 178. When released, the releasable seal also forms a vent forthe evacuated air.

As shown more clearly in FIG. 8, the plunger rod 140 includes a distalend 141, a proximal end 149, and an elongate body 142 extending from thedistal end 141 and the proximal end 149. The plunger rod 140 may be madeof a rigid plastic or other material that has a greater rigidity thanthe stopper 160. Examples of such materials include polypropylene,polyethylene, polycarbonate and combinations thereof. As illustrated inFIG. 8, the elongate body 142 may be cylindrical. The shape of theelongate body 142 may be rectangular, or may be formed by twoperpendicularly intersecting beams.

The proximal end 149 of the plunger rod 140 includes an optionalthumbpress 148. The distal end 141 of the plunger rod 140 includes astopper-engaging portion 150. In accordance with one or more embodimentsof the present invention, the stopper-engaging portion 150 is shaped tofit within the stopper cavity 166 of the stopper 160 and to retain thestopper 160 at the distal end 141 of the plunger rod. In a specificembodiment, the plunger rod 140 and stopper 160 may be integrally formedor permanently attached, while allowing the stopper 160 to expand andcompress.

The stopper-engaging portion 150 has a size and shape to allow aslidable engagement between the plunger rod 140 and the stopper 160.Specifically, the stopper-engaging portion 150 of the plunger rod may beable to slide distally and proximally within the stopper cavity 166 ofthe stopper 160, while maintaining the attachment or engagement betweenthe plunger rod 140 to the stopper 160.

In the embodiment more clearly shown in FIGS. 9 and 9A, thestopper-engaging portion 150 includes a tapered neck portion 156distally adjacent the elongate body 142 of the plunger rod 140. A firstprotrusion 152 is positioned distally adjacent the tapered neck portion156, a boss member 153 distally adjacent the first protrusion 152 and asecond protrusion 154 distally adjacent the boss member 153. The firstprotrusion 152 has a cross-sectional width to prevent separation of theplunger rod 140 from the stopper 160 and, more specifically, theseparation between the plunger rod 140 from the rim 179 of the stopper160. The second protrusion 154 includes a perpendicular face 158, whichhave a cross-sectional width equal to or greater than thecross-sectional width of opening 171 and/or the porous portion 190 toblock the air evacuated into the stopper cavity 166 from entering thechamber 118 of the syringe barrel 110 or other container duringexpulsion of the aspirated liquid from the syringe barrel 110. In suchembodiments, the second protrusion 154 blocks or covers the opening 171and/or porous portion 190 and forces the air within the stopper cavity166 of the stopper to escape through the aperture 178 when thereleasable seal between the tapered neck portion 156 of the plunger rodand rim 179 and/or undercut 173 of the stopper 160 is released.

The first and/or second protrusions 152, 154 may be disc shaped. Thefirst and/or second protrusions 152, 154 may have a rectangular orsquare cross-section. Alternative constructions may provide a variety ofshapes, which may be identical to each other or different from eachother. The first protrusion 152 may be shaped to prevent separation ofthe plunger rod from the stopper. The second protrusion 154 may beshaped to prevent air that has already been evacuated into the stoppercavity 166 from entering the chamber 118 through the porous portion 190,for example, as a force in the distal direction is applied to theplunger rod to expel the liquid from within the chamber 118.

The boss member 153 and/or the stopper 160 have a length that permitsthe stopper-engaging portion 150 to move distally and proximally withinthe stopper cavity 166 of the stopper 160 a pre-selected axial distanceD1 relative to the stopper 160, as shown more clearly in FIG. 11. In aspecific embodiment, the boss member 153 has a length that permits suchmovement of the plunger rod 140 without separation of the plunger rod140 from the stopper 160. In one or more embodiments, the movement ofthe plunger rod 140 for the length D1 relative to the stopper 160permits the plunger rod 140 and the first protrusion 152 to exert enoughforce on the inside surface 164 of the stopper to facilitate theexpansion of the expandable portion 162 of the stopper. Thecross-sectional width and length of the boss member 153 may be sized toallow the stopper-engaging portion 150 to fit within the stopper cavity166 of the stopper 160 when the stopper 160 is an unexpanded orcompressed state.

The tapered neck portion 156 of the stopper-engaging portion 150 may beshaped to form a seal with the rim 179 of the stopper 160 at theaperture 178. As will be described more fully below, formation of a sealbetween the plunger rod 140 and the rim 179 at the aperture 178 of thestopper ensures a vacuum is created between the distal face 174 of thestopper 160 and the chamber 118 of the syringe barrel 110 or othercontainer so that fluid may be aspirated into the chamber 118. Inembodiments where the seal is releasable, the structure of thestopper-engaging portion 150 and/or plunger rod 140 prevents the sealfrom being released during aspiration but permits the release of theseal when the liquid is being expelled from the chamber 118 of thesyringe barrel 110 so the air within the stopper cavity 166 may bevented.

In a specific embodiment, the tapered neck portion 156 of the stopperengaging-portion 150 may be shaped to form a releasable seal with therim 179 at the aperture 178 of the stopper. As shown more clearly inFIG. 9A, the tapered neck portion 156 has a cross-sectional width thatincreases from the elongate body 142 of the plunger rod to the firstprotrusion 152. Alternatively, the cross-sectional width of the taperedneck portion 156 increases at the same angle as the angle of theundercut 173 of the stopper 160. In accordance with a specificembodiment, the tapered neck portion 156 is contoured so that at leastone portion of the tapered neck portion 156 forms a fluid-tightengagement with the undercut 173 as the plunger rod 140 and stopper 160move in the proximal direction. In one or more embodiments, the taperedneck portion 156 forms a seal with the rim 179 of the stopper 160 thatcan be formed and released as the plunger rod 140 moves distally andproximally relative to the stopper 160.

In use, as shown in FIGS. 8-13, the plunger rod 140 and stopper 160 areassembled as medical device 100 and are inserted into the open proximalend 119 of the syringe barrel 110. Before aspirating fluid into thechamber 118 of the syringe barrel 110 or other container, the distalface 174 of the stopper 160 is positioned adjacent to the distal wall112 of the syringe barrel 110, so the air within the chamber 118 isminimized and is primarily present in the tip 120 of the syringe barrel110 or other container. In one or more embodiments, the distal face 174is flexed concavely to further minimize the air within the chamber 118by applying a force to the plunger rod in the distal direction, prior toaspirating liquid into the chamber 118. In addition, the expandableportion 162 of the stopper 160 is configured to a compressed state (asalso shown in FIGS. 3-5 and 8). Before use, the user may compress thestopper before assembly with the plunger rod 140 and the syringe barrel110 and/or other container.

To fill the chamber 118 of the syringe barrel 110 or other container,the needle cannula 184 is inserted into a container, such as a vial 50,to draw the liquid from a vial into the chamber 118 of the syringebarrel 110, as shown in FIG. 9. Thereafter, a proximally directed forceis applied to the plunger rod 140 so that the stopper-engaging portion150 applies a proximally directed force to the inside surface 164 of theproximal wall 176 of the stopper. The application of this proximallydirected force causes or allows the expandable portion 162 to expand toan expanded state, as demonstrated in FIGS. 8, 9 and 9A. The taperedneck portion 156 forms a seal with the rim 179 and undercut 173. Theexpansion of the expandable portion 162 creates a “spring back” motionthat creates a vacuum within the stopper cavity 166 of the stopper 160,drawing air and liquid into the chamber 118. The porous portion 190 ofthe stopper permits air present within the chamber 118 and/or tip 120 topermeate therethrough into the stopper cavity 166 of the stopper. Thevacuum within the stopper cavity 166 draws air and possibly liquid intothe chamber 118 prior to the creation of a vacuum within the chamber 118caused by the movement of the stopper 160 in the proximal direction. Theexpansion of the expandable portion 162 may draw some liquid into theneedle cannula 184 and chamber 118 before the stopper 160 moves,however, the porous portion 190 prevents liquid from permeating throughthe porous portion 190 into the stopper cavity 166. Expansion of theexpandable portion 162 shown in FIGS. 3-5 is shown in FIGS. 6 and 7,where the single inward bend or single pinched area is released and thelength and/or cross-sectional width of the bendable wall 172 expands toexpand the size or volume of the stopper cavity 166.

During use, the user may apply a continuous force on the plunger rod 140and stopper 160 without having to wait for the air to be drawing intothe stopper cavity 166 from the chamber 118. As shown in FIG. 10, thecontinued application of a proximally directed force to the plunger rod140 during a normal aspiration step causes the plunger rod 140 andstopper 160 to move together in the proximal direction. The peripheralseal 170 of the stopper 160 forms a fluid-tight seal with the interiorsurface 116 of the syringe barrel 110 or other container and the taperedneck portion 156 continues to form a seal with the rim 179 and undercut173. The movement of the plunger rod 140 and stopper 160 in the proximaldirection creates a vacuum within the chamber 118. The air drawn intothe chamber 118 rises above the liquid toward the stopper 160 andpermeates through the porous portion 190 into the stopper cavity 166 ofthe stopper.

In some instances, as shown in FIGS. 9-11, the syringe barrel 110 willbe positioned vertically so that the liquid aspirated into the chamber118 forms a column of liquid and air trapped within the chamber 118rises to the top of the liquid column. The air then permeates throughthe porous portion 190 into the stopper cavity 166 of the stopper 160.As this occurs, the liquid forms a column that approaches the porousportion 190 until the air is evacuated from the chamber 118 into thestopper cavity 166 and no air remains in the chamber 118, as shown inFIG. 11. As otherwise described herein, the porous portion 190 preventsthe liquid from permeating through the porous portion into the stoppercavity 166. In one or more embodiments, the fluid-tight seal between theperipheral seal 170 and interior surface 116 of the syringe barrel andthe application of a proximally directed force to the plunger rod 140and stopper 160 causes the distal face 174 to flex concavely. As shownin FIG. 10, the concave shape of the distal face 174 during aspirationpermits more air to permeate through the porous portion 190 before theliquid reaches the porous portion 190. After the desired amount ofliquid is aspirated in to the chamber 118, the porous portion 190prevents liquid from entering the stopper cavity 166 and the liquid maybe expelled from the chamber 118 without taking any additional steps toremove air from the chamber 118.

To expel the liquid contained within chamber 118, a distally directedforce is applied to the plunger rod 140, causing the plunger rod 140 tomove the pre-selected axial distance D1, as shown in FIG. 11, in thedistal direction relative to the stopper while the stopper 160 remainsstationary, as shown in FIG. 12. Movement of the plunger rod 140 in thedistal direction relative to the stopper 160 releases the proximallydirected force that was applied to the inside surface 164 of theproximal wall 176 of the stopper by the plunger rod 140. The release ofthe proximally directed force on the inside surface 164 of the proximalwall 176 allows the expandable portion 162 of the stopper to collapsesor compress into an unexpanded state. Thereafter, the plunger rod 140and stopper 160 to move together in the distal direction. The peripheralseal 170 of the stopper 160 continues to form a fluid tight seal withthe interior surface 116 of the syringe barrel 110. As the aspiratedliquid is expelled, the expandable portion 162 of the stopper 160remains collapsed or compressed in an unexpanded state.

In embodiments where the seal formed between the rim 179 at the aperture178 of the stopper and tapered neck portion 156 of the plunger rod isreleasable, the movement of the plunger rod 140 in the distal directionrelative to the stopper 160, which is stationary, releases the seal andallows the air contained within the stopper cavity 166 to be releasedthrough the aperture 178. In a specific embodiment, the distal movementof the plunger rod 140 relative to the stopper 160 permits theperpendicular face 158 of the stopper engaging portion 150 to cover theporous portion 190 and block the conduit 175 and prevent the aircontained within the stopper cavity 166 from escaping through the porousportion 190 toward the chamber 118. The position of the perpendicularface 158 over the porous portion 190 forces the air to escape throughthe aperture 178 or remain within the stopper cavity 166 of the stopper.

In an alternative embodiment, the plunger rod 140 may be locked in afixed relationship with respect to the stopper after the initial distalmovement of the plunger rod 140 relative to the stopper 160. Forexample, the distal end 161 of the stopper 160 may include a rim orother locking structure (not shown) for retaining the second protrusion154 of the plunger rod 140. Thereafter, the plunger rod 140 and stopper160 move together in the proximal and distal directions in a fixedrelationship. In such embodiments, the expandable portion 162 of thestopper collapses or compresses to an unexpanded state as the plungerrod 140 and the stopper 160 move together in the proximal and distaldirections. In one or more embodiments, the expandable portion 162 ofthe stopper 160 resists compression so that the air within the stoppercavity 166 does not escape through the porous portion 190 in the distaldirection and remains within the stopper cavity 166.

As shown in FIGS. 12 and 13, the continued application of a distallydirected force to the plunger rod 140 or continuous movement of theplunger rod 140 and stopper 160 in the distal direction causes theperpendicular face 158 of the stopper-engaging portion 150 to contactthe inside surface 164 of the stopper 160 adjacent to the conduit 175and causes the plunger rod 140 and stopper 160 to move in the distaldirection together. In one or more embodiments that utilize a stopper160 having a distal face 174 that flexes, the application of acontinuous and distally directed force to the plunger rod 140 causes thedistal face 174 to flex convexly as the distal face 174 contacts thedistal wall 112 of the syringe barrel 110. In embodiments which utilizea stopper 160 having a convexly-shaped distal face 174, the distal face174 conforms more closely to the distal wall 112 upon contact with thedistal wall 112. In accordance with one or more embodiments, the convexshape of the distal face 174 forces more liquid out of the chamber 118,allowing more accurate dosing, as shown in FIG. 13.

A second aspect of the present invention pertains to a medical device200 that utilizes a stopper assembly, including a stopper 260 and astopper hub 250, wherein the stopper hub 250 utilizes a pump body 253.In one or more embodiments, the pump body 253 includes a bendable wallin the shape of a bellows or having corrugated or accordion-style walls.One or more embodiments according to the second aspect of the presentinvention are shown in FIGS. 14-25. As used herein, the term “bellows”as used herein is used to describe a structure possessed by what aretraditionally referred to as bellows or accordion-style walls. The term“bellows” also includes the alterable structure achieved by repeatedcorrugations or bends extending around the circumference or perimeter ofa body. The term “bellows” also includes other deformable containers orflexible or semi-flexible fluid enclosures or containers that may holdfluid and function as a pump, such as diaphragm devices, springs, andthe like.

The medical device 200 shown in FIGS. 14-25 includes a plunger rod 240attached to stopper hub 250 that is attached or integrally formed to astopper 260. For illustration, the medical device 200 is shown in usewith a container in the form a syringe barrel 210 with a needle cannula284 attached thereto. As shown more clearly in FIG. 14, the syringebarrel 210 includes an open proximal end 219 and a distal end 211 and adistal wall 212. A sidewall 214 extends from the distal end 211 to theopen proximal end 219 and includes an interior surface 216 that definesa chamber 218 for retaining or holding fluids, which may include liquidmedication and/or other liquids. The distal end 211 may also include atip 220 having an open passageway 222 therethrough in fluidcommunication with the chamber 218. As shown, the distal end 211 of thesyringe barrel 210 includes an optional luer fitting 288. The openproximal end 219 of the syringe barrel 210 may include a flange 224. Aneedle cannula 284 including a lumen 286 or opening therethrough and maybe attached to the tip 220 so that the lumen 286 is in fluidcommunication with the open passageway 222 and the chamber 218. In theembodiments shown in FIGS. 14-23, a needle cannula 284 is attacheddirectly to the tip 220. Alternatively, a needle hub (not shown) may beused to attach a needle to the tip. The interior surface 216 of thesyringe barrel 210 may have a smooth surface that is free of anyprotrusions or depressions. In use, the plunger rod 240, stopper hub 250and stopper 260 are inserted into the open proximal end 229 of thesyringe barrel 210.

As more clearly shown in FIGS. 15 and 16, the stopper 260 includes adistal end 261 and an open proximal end 269. The stopper 260 includesbody 262 extending from the distal end 261 to the open proximal end 269,an outside surface 263 and an inside surface 264 defining a stoppercavity 266. In one or more embodiments, the inside surface 264 of thebody 262 may include a peripheral channel 268 forming a groove or ridgewithin the body for engagement with the stopper hub 250, as will bedescribed in detail below and is shown more clearly in FIG. 16. As shownin FIGS. 14-22, the outside surface 263 of the body 262 includes asealing portion 270. As shown, the sealing portion 270 is disposed onthe outside surface 263 adjacent the distal end 261, however, it mayalso be formed at any location on the outside surface 263 along thelength of the body 262. The stopper 260 may be formed from anelastomeric material, polymeric material or other suitable materialknown in the art. In one or more embodiments, the sealing portion 270may includes one or more grooves (not shown) shaped to form afluid-tight seal with the inside surface of a syringe barrel. In one ormore embodiments, the sealing portion 270 may have a circularcross-section for forming a fluid-tight seal with a syringe barrelhaving an interior surface with a circular cross-section. The sealingportion 270 may be formed from a material suitable for forming afluid-tight seal with the interior surface 216 of the syringe barrel andmay include the same or different material utilized to form the stopper260.

The distal end 261 of the stopper 260 includes a convex distal face 272having an opening 274 therethrough in fluid communication with thestopper cavity 266. The distal end 261 of the stopper may also include apath 276 in fluid communication with the stopper cavity 266 and theopening 274. As shown in FIGS. 14-25, the distal face 272 may be shapedconvexly so that it conforms more closely to the shape of the distalwall 212 of the syringe barrel 210 to expel as much liquid from thechamber 218 as possible. In one or more embodiments, the distal face 272may be flexible (not shown) and may flex concavely and convexly.

A porous portion 290 is disposed in the path 276 and/or opening 274 andin fluid communication with the path 276, stopper cavity 266 and theopening 274. In one or more embodiments, the porous portion 290 is airpermeable and liquid impermeable. In other words, the porous portion 290forms a selective barrier that a liquid penetration pressure and an airpenetration pressure that is less than the liquid penetration pressure.

In one or more embodiments, the porous portion 290 has a circular shape.Alternatively, the porous portion 290 may have a square and/orrectangular shape. In one or more embodiments, the porous portion 290may be integrally formed or disposed on the distal face 272, adjacent tothe opening 274. In a specific embodiment, the porous portion has across-sectional width that is smaller than the cross-sectional width ofthe distal face 272. The porous portion may also be integrally formedand/or disposed adjacent to the path 276 on the inside surface 264 ofthe stopper. In a specific embodiment, the porous portion 290 may have across-sectional with that is smaller than the cross-sectional width ofthe inside surface 264 of the stopper.

The porous portion 290 may be integrally formed on the distal face 272,with the peripheral edges of the distal face 272 and the sealing portion270 remaining non-porous. Alternatively, the porous portion 290 isseparated from the sealing portion 270 by the distal face 272.

The porous portion 290 may also be shaped to fit within the opening 274and form a fluid-tight engagement with the opening 274. For example, theporous portion 290 may extend from the distal face 272 into the path276. The porous portion 290 may have a periphery that is molded to aportion of the distal face 272. In one or more embodiments, the porousportion 290 may be attached to the distal face 272 of the stopper bymechanical means, for example, adhesives and/or molding. In a specificembodiment, the distal face 272 may include a pocket (not shown) forholding and securing the porous portion 290 adjacent to the distal face272 and the opening 274.

The stopper hub 250 includes an open distal end 251 and an open proximalend 259. The stopper-engaging portion 252 includes an aperture 255 influid communication with the stopper cavity 266, path 276 and opening274. The open distal end includes a stopper-engaging portion 252, whichmay be provided in the form of a disc extending radially outwardly, forattachment of the stopper hub 250 to the stopper 260. Specifically, asmore clearly shown in FIG. 19, the stopper-engaging portion 252 extendsradially outwardly to engage the peripheral channel 268 of the stopper260. In one or more embodiments, the stopper-engaging portion 252 may bein the form of a tab (not shown), which corresponds to an opening orother corresponding structure on the inside surface 264 of the stopper.In a specific embodiment, the stopper-engaging portion 252 may have anopening and the inside surface 264 of the stopper may include a tabextending radially inwardly to engage with the opening of the stopper260. Other means to engage the stopper hub 250 to the stopper 260 mayalso be utilized. Alternatively, the stopper 260 may be integrallyformed on the distal end 251 of the stopper hub 250 and the stopper 260and the stopper hub 250 may be provided as a single unit.

The stopper hub 250 includes a pump body 253 and a plunger engagingportion 230 for attaching the stopper assembly to a plunger rod, as willbe described in more detail below. The pump body 253 includes a wall 254defining a pump cavity 258 in fluid communication with the opening 274and the stopper cavity 266. In use, the pump body 253 is utilized tocreate a vacuum within the stopper hub 250 and stopper 260 assembly byoperating as a positive displacement pump to expand the pump cavity 258when sealed. The pressure difference between the pump cavity 258 and thechamber 218 and stopper cavity 266 draws air and possibly liquid withinthe chamber 218 into the pump cavity 258. To expand the pump cavity, thewall 254 is provided in the shape of a bellows or having a plurality ofcorrugations that can fold into one another to collapse and expand thelength of the wall 254. The pump cavity 258 has a volume that varies asthe wall 254 expands and collapses.

The wall 254 may be configured to compress and remain compressed uponapplication of a force on the pump body 253 in the distal direction. Thewall 254 may be configured expand and remain in an extended length whenno force is being applied the bellows. In this regard, the wall 254 mayinclude a spring-type insert (not shown) that maintains an extendedlength or expanded state and may require a force to be applied to it toreach a compressed state. The wall 254 may require a continuous force tobe applied to it or compressing force to remain in a compressed state.In a more specific embodiment, the wall 254 is formed from anelastomeric material. The elastomeric material can be used to form thewall and may be modified so that the wall 254 possesses a springconstant that allows rapid expansion from a compressed state. The pumpbody 253 may resist compression after air enters the pump cavity 258.

In the embodiments shown in FIGS. 14-25, the wall 254 includes two bends256, 257 that fold together to shorten or collapse the length of thewall 254 The wall 254 may include more than two bends or corrugationsor, alternatively, include a single bend or corrugation. The volume ofthe pump cavity 258 expands and contracts as the length of the wall 254increases and decreases. Changes in the length and/or cross-sectionalwidth of the wall 254 cause the pump body 253 to compress to acompressed state and expand to an expanded state, as shown in FIGS. 19and 20. The length and/or cross-sectional width of the wall 254 maydecrease as an initial force is applied to the plunger rod 240 in thedistal direction. This occurs, for example, when the plunger rod 240,the stopper hub 250 and the stopper 260 are assembled within the chamber218 of a syringe barrel 210 and an initial force is applied to theplunger rod 240 in the distal direction to “bottom” or “park” themedical device 200 within the syringe barrel so the distal face 272 isadjacent the distal wall 212 of the syringe barrel. In one or moreembodiments, the length and/or cross-sectional width of the wall 254increases as the force applied to the plunger rod 240 in the distaldirection is released. In a specific embodiment, the length and/orcross-sectional width of the wall 254 increases as an initial force isapplied to the stopper 260 in the proximal direction, for example,during aspiration of a syringe barrel.

Alternatively, the wall 254 resists compression after expansion. In oneor more embodiments, the wall 254 is molded or formed to have a geometrythat creates a spring-like effect or reaction to the application offorces in the distal and/or proximal direction. In a specificembodiment, the wall 254 is initially in an expanded state and mayrequire application of a force to be compressed. The wall 254 may beformed from an elastomeric material or other material that has a springconstant to expand and compress during normal operation of the medicaldevice 200 and syringe barrel 210. Specifically, in one or moreembodiments, the wall 254 has a spring constant that permits expansionin a rapid manner in a rapid manner so the user does not experience anysignificant tactile response to the expansion and/or is not required totake active steps to expand the stopper 260. In one or more embodiments,the spring constant of the wall 254 may be modified depending on theapplication and the viscosity of the liquid to be aspirated into thesyringe barrel 210.

As shown in FIGS. 15-16, the wall 254 is compacted inwardly at the twobends 256, 257 to have a reduced length and/or cross-sectional width ofthe pump body 253, resulting in reducing the size or volume of the pumpcavity 258. It will be understood the wall 254 may curve inwardly toreduce the length and/or cross-sectional width of the pump body 253.Alternatively, the pump body 253 may include a collapsible wall (nowshown) having more than one telescoping segment that reduce and expandthe length of the pump body 253.

The length and/or cross-sectional width of the pump body 253 of thestopper may be pre-determined for specific applications. In one or moreembodiments, the length and/or cross-sectional width of the pump body253 may be sized to draw in a pre-determined amount of air trappedwithin a syringe barrel. The length and/or cross-sectional width of thepump body 253 may be sized to draw in a pre-determined amount of airtrapped within the tip of a syringe. In a more specific embodiment, thevolume of the pump cavity 258 may be sized to hold a pre-determinedamount of air trapped within a syringe barrel. In a specific embodiment,the volume of the pump cavity 258 may be sized to hold a pre-determinedamount of air trapped within the tip of a syringe.

The stopper hub 250 includes a plunger-engaging portion 230 thatincludes an open distal end 231 and an open proximal end 239 and aninside surface 233 defining a socket 235 configured to frictionallyengage the outside surface of the plunger rod 240, as will be describedbelow. As shown in FIG. 16, the socket 235 includes a groove 236disposed along the inside surface 233 forming a fitting for the distalend of the plunger rod. In one or more embodiments, a plurality ofgrooves may be disposed along the inside surface 233 for gripping thedistal end of the plunger rod 240. In a specific embodiment, theplunger-engaging portion 230 includes one or more indentations (notshown) disposed along the inside surface 233 for receiving the distalend of the plunger rod 240, which may include a plurality ofcorresponding tabs (not shown) which form a frictional fit with theindentations. Alternatively, the inside surface 233 may have a texturedsurface or a coating (not shown) that creates or increases frictionalinterference with the distal end of the plunger rod 240. In anotheralternative configuration, the plunger rod 240 and stopper hub 250 maybe integrally formed or permanently attached using methods know in theart.

The distal end 231 of the plunger-engaging portion includes an outlet237 and a valve 238. The outlet 237 is in fluid communication with thesocket 235. The valve 238 comprises a one-way valve configured to opento permit fluid communication between the pump cavity 258 and the outlet237. The outlet 237, when sealed, facilitates the formation of a vacuumwithin the chamber 218 of the syringe. The valve 238 may be in form ofany one-way valve or check valve that opens in one direction.

In one or more embodiments, the valve 238 provides a means for ventingthe air evacuated into the pump cavity 258. In a specific embodiment,the valve 238 provides a relief valve for the pump cavity 258. In one ormore embodiments the distal end of the plunger-engaging portion does notinclude a valve 238 and the outlet 237 is in fluid communication withthe pump cavity 258. In a specific embodiment, the distal end of theplunger rod 240 is enclosed and does not include an outlet 237 or avalve 238.

In one or more embodiments which incorporate a valve 238, the valve 238closes during expansion of the wall 254 and seals the outlet 237 fromthe socket 235. During compression or when the wall 254 is collapsing,the valve 238 opens. In one or more embodiments, the valve 238 is in theform of a flap.

In use, a plunger rod 240 is attached to the proximal end 259 of thestopper hub. The plunger rod 240 shown more clearly in FIG. 14 includesa distal end 241, a proximal end 249, and an elongate body 242 extendingfrom the distal end 241 and the proximal end 249. The plunger rod 240may be made of a rigid plastic or other material that has a greaterrigidity than the stopper 260. Examples of such materials includepolypropylene, polyethylene, polycarbonate and combinations thereof. Theelongate body 242 may be cylindrical. In one or more embodiments, theshape of the elongate body 242 may be rectangular or other shape. Theproximal end 249 of the plunger rod 240 includes an optional thumbpress248. The body 242 may include a cavity (not shown), which may be influid communication with the pump cavity 258.

The distal end 241 of the plunger rod includes a structure for engagingthe stopper hub 250. As shown in FIGS. 14 and 16, the distal end 241 ofthe plunger rod includes such a structure for engaging the stopper hub250 in the form of a distal portion 245, having a disc-shaped plug 243disposed perpendicularly to the elongate body 242 of the plunger rod. Inone or more embodiments, the disc-shaped plug 243 may include a beveledadjacent to the distal end 241 of the plunger rod. In a specificembodiment, the disc-shaped plug 243 includes one beveled edge disposedon the distal side of the plug 243 and one beveled edge on the proximalside of the plug 243. The beveled edge may be formed around theperiphery of the disc-shaped plug 243. The distal end 241 of the plungerrod 240 may include an optional a neck portion 244 proximally adjacentto the disc-shaped plug 243 disposed between the disc-shaped plug 243and the distal portion 245. The plunger rod 240 may also include twoperipheral ribs 246, 247 disposed along the elongate body 242 andpositioned proximally adjacent the neck portion 244. In one or moreembodiments, the plunger rod 240 may not include a neck portion 244 andthe disc-shaped plug 243 may be formed at the distal end of the plungerrod 240 adjacent to the elongate body 242. As shown in FIG. 16, thedistal portion 245 includes a recess 292 allowing space for the valve238 to open, as will be described below.

In use, as shown in FIG. 17, the plunger rod 240 including a recess,stopper hub 250 and stopper 260 are assembled as a medical device 200and are inserted into the open proximal end 219 of the syringe barrel210. Before aspirating fluid into the chamber 218 of the syringe barrel210 or other container, the distal face 272 of the stopper 260 ispositioned adjacent to the distal wall 212 of the syringe barrel 210, sothat the air within the chamber 218 is minimized and is primarilypresent in the tip 220 of the syringe barrel 210 or other container.

In the assembled state, the stopper hub 250 and the plunger rod 240 forma unitary piece that moves together distally and proximally within thechamber. The wall 254 causes the stopper 260 to remain stationary withrespect to movement of the plunger rod 240, as the length of the stopperhub 250 is elongated or expanded.

As shown in FIG. 17, the wall 254 is in an expanded state before use. Tocreate a vacuum within the pump cavity 258, which causes the evacuationof air from the syringe, an initial distally directed force is appliedto the plunger rod 240, as shown in FIGS. 18 and 19. The user may insertthe needle cannula 284 into a vial and submerge it into the liquidapplying the force to the plunger rod 240 in the distal direction tocompress the wall 254. The compression of the wall 254, after insertingthe needle cannula 284 into vial 50, causes air within the pump cavity258 to escape through the needle cannula 284 and lumen 286 and alsopossibly through the open valve 238, which opens during compression ofthe wall 254, as shown in FIGS. 18 and 19.

Alternatively, the user may apply a force in the distal direction to theplunger rod 240 and compress the wall 254 prior to inserting the needlecannula 284 into the vial 50 (not shown). The user would continue toapply the distally directed force on the plunger rod 240 and thensubmerge the lumen 286 in the liquid contained within the vial. Thecompression of the wall 254 prior to inserting the needle cannula 284into vial 50, causes air within the pump cavity 258 to escape throughthe lumen 286 and the open valve 238 and outlet 237, which opens duringcompression of the wall 254.

After submerging the lumen 286 into the liquid contained within the vial50, the user releases the force applied to the plunger rod 240 in thedistal direction. The spring constant and properties of the wall 254cause the wall 254 to expand from the compressed state to an expandedstate upon the release of the force applied on the plunger rod 240 inthe distal direction. The release of the force applied to the plungerrod 240 also causes the stopper 260 to remain stationary and causes theplunger rod 240 to move proximally, as the length of the wall 254expands. The expansion of the pump cavity 258 creates a vacuum withinthe pump cavity 258, which causes the valve 238 to close, as shown moreclearly in FIGS. 20 and 21.

The expansion of the pump cavity 258 causes any air present within theneedle cannula 284 and the syringe barrel 210 to be evacuated into thepump cavity 258, through the porous portion 290 of the stopper 260. Inone or more embodiments, the expansion of the pump cavity 258 may causesome liquid to be drawn into the tip 220 and/or chamber 218 prior to theformation of a vacuum within the chamber 218 caused by movement of thestopper 260 in the proximal direction. The porous portion 290 preventsthis liquid from entering the stopper cavity 266, as will be describedbelow.

As shown in FIG. 23, to actively aspirate the desired amount of liquidinto the syringe barrel 210, the user applies a proximally directedforce on the plunger rod 240 or, more specifically, the thumbpress 248,which draws the liquid from the vial 50 into the needle cannula 284 andinto the chamber 218. The valve 238 remains closed and the vacuum withinthe pump cavity 258 is maintained and continues to draw any air presentin the chamber 218 into the pump cavity 258. In use, the movement of theplunger rod 240 relative to the stopper 260, when the wall 254 isexpanded, and movement of the plunger rod 240, stopper hub 250 andstopper 260 together in the proximal direction occurs as part of acontinuous aspiration stroke that is similar to an aspiration strokeusing conventional syringes known in the art.

As shown in FIGS. 23A-B, as liquid fills the chamber 218, any remainingair rises to the top of the aspirated liquid or between the liquid andthe distal face 272 of the stopper 260. This remaining air permeatesthrough the porous portion 290 and the liquid is prevented from passingthrough the porous portion 290 into the stopper cavity 266. The porousportion may be formed from hydrophobic filter, a swellable polymer andcombinations thereof, as described herein. When the porous portionincludes a swellable polymer, the openings present in the swellablepolymer close upon contact with the liquid. In embodiments which includea porous portion including a hydrophobic filter or membrane, thehydrophobic filter prevents liquid from permeating through the porousportion 290 and entering the stopper cavity 266. FIG. 23B illustrates asyringe barrel 210 filled with liquid and no air.

The valve 238 remains closed as the pressure within the pump cavity 258remains lower than the pressure outside of the pump cavity 258. Forexample during aspiration, as the wall 254 of the pump body expands, thevacuum created within the pump cavity 258 draws the in valve 238 orforces the valve 238 closed. As the pressure within the pump cavity 258equalizes or, as will be discussed, the user expels the liquid withinthe chamber 218, the valve 238 opens and vents the evacuated air fromwithin the pump cavity 258.

To expel the fluid, a distally directed force is applied to the plungerrod 240 and the stopper hub 250 move with the stopper 260 in the distaldirection. As shown in FIG. 24, the force applied to the plunger rod inthe distal direction overcomes the resistance between the sealingportion 270 of the stopper 260 and the interior surface of the syringebarrel 210 and also the resistance of the wall 254 to collapsing. Thecompressed wall 254 causes the valve 238 to open and allows the airwithin the pump cavity 258 to escape through the outlet 237 instead ofthrough the porous portion 290. The recess 292 of the plunger rodprovides space for the valve 238 to open.

In embodiments which utilize a flexible distal face, the application ofa continuous and distally directed force on the plunger rod 240 causesthe distal face 272 to flex as the distal face 272 contacts the distalwall 212 of the syringe barrel. As shown in FIG. 25, in embodiments thatutilize a stopper 260 having a convexly-shaped distal face 272, thedistal face 272 conforms more closely to the distal wall 212 uponcontact with the distal wall 212. The convex shape of the distal face272 upon contact with the distal wall 212 expels even more liquid fromthe syringe barrel 210.

FIGS. 26-34 illustrate a medical device 300 according a third aspect ofthe invention. The medical device 300 includes a plunger rod 340 thatmay be attached to a stopper hub 350 and stopper 360 assembly. Forillustration, the medical device 300 is shown in use with a container inthe form a syringe barrel 310 with a needle cannula 384 attachedthereto. As shown more clearly in FIGS. 26 and 29A, the syringe barrel310 includes an open proximal end 319 and a distal end 311 and a distalwall 312. A sidewall 314 extends from the distal end 311 to the openproximal end 319 and includes an interior surface 316 that defines achamber 318 for retaining or holding fluids, which may include liquidmedication and/or other liquids. The distal end 311 may also include atip 320 having an open passageway 322 therethrough in fluidcommunication with the chamber 318. A needle cannula 384 includes alumen 386 or opening therethrough and may be attached to the tip 320 sothat the lumen 386 is in fluid communication with the open passageway322 and the chamber 318. In the embodiments shown in FIG. 26, a needlecannula 384 is attached to the tip 320. Alternatively, a needle hub (notshown) may be used to attach a needle to the tip. As shown in FIG. 26,the distal end 311 includes an option luer fitting 388 and the proximalend 319 includes an optional finger flange 324. The interior surface 316of the syringe barrel 310 may have a smooth surface that is free of anyprotrusions or depressions. In use, the plunger rod 340, stopper hub 350and stopper 360 are inserted into the open proximal end 319 of thesyringe barrel 310.

As more clearly shown in FIGS. 27 and 28, the stopper 360 includes adistal end 361 and an open proximal end 369. The stopper 360 includes astopper body 362 extending from the distal end 361 to the open proximalend 369 that includes an inside surface 364 defining a stopper cavity366. In one or more embodiments, the inside surface 364 of the stopperbody 362 may include a peripheral channel 368 forming a groove or ridgewithin the stopper body 362 for engagement with the stopper hub 350, aswill be described in detail below. As shown in FIGS. 26-34, the stopperbody 362 includes an outside surface 363 with a sealing portion 370. Asshown, the sealing portion 370 is formed adjacent the distal end 361,however, the sealing portion 370 may also be formed along the entirelength of the outside surface 363 or at other locations along the lengthof the outside surface. The stopper 360 may be formed from anelastomeric material, polymeric material or other suitable material. Thesealing portion 370 includes at least one peripheral edge 372 shaped toform a fluid-tight seal with the inside surface of a syringe barrel. Thesealing portion 370 and/or the peripheral edge 372 may be formed from amaterial suitable for forming a fluid-tight seal with the interiorsurface 316 of the syringe barrel, which may include the same ordifferent material as the stopper 360. In one or more embodiments, theperipheral edge 372 may have a circular cross-section for forming afluid-tight seal with a syringe barrel having an interior surface with acircular cross-section.

The distal end 361 of the stopper 360 includes a convex distal face 374having an opening 376 therethrough in fluid communication with thestopper cavity 366. The distal end 361 of the stopper may also include apath 378 in fluid communication with the stopper cavity 366 and theopening 376. In one or more embodiments, the distal face 374 is flexibleand flexes concavely and convexly, as will be described in greaterdetail below. The distal face 374 may also be shaped convexly so that itconforms more closely to the shape of the distal wall 312 of the syringebarrel 310 to expel as much liquid from the chamber 318 as possible.

A porous portion 390 is disposed in the path 378 and/or opening 376 andin fluid communication with the path 378, stopper cavity 366 and theopening 376. In one or more embodiments, the porous portion 390 is airpermeable and liquid impermeable. In other words, the porous portion 390forms a selective barrier that a liquid penetration pressure and an airpenetration pressure that is less than the liquid penetration pressure.

The porous portion 390 may have a circular shape. Alternatively, theporous portion 390 may have a square and/or rectangular shape. In one ormore embodiments, the porous portion 390 may be integrally formed ordisposed on the distal face 374, adjacent to the opening 376. In aspecific embodiment, the porous portion 390 has a cross-sectional widththat is smaller than the cross-sectional width of the distal face 374.The porous portion 390 may also be integrally formed and/or disposedadjacent to the path 378 on the inside surface 364 of the stopper. Theporous portion 390 may have a cross-sectional width that is smaller thanthe cross-sectional width of the inside surface 364 of the stopper. Thethickness of the porous portion 390 may be adjusted so the porousportion extends along the length of the path 378.

The porous portion 390 may be integrally formed on the distal face 374,with the peripheral edges of the distal face 374 and the sealing portion370 remaining non-porous. In a specific embodiment, the porous portion390 is separated from the sealing portion 370 by the distal face 374.

The porous portion 390 may also be shaped to fit within the opening 376and form a fluid-tight engagement with the opening 376. For example, theporous portion 390 may extend from the distal face 374 into the path378. In one or more embodiments, the porous portion 390 may have aperiphery that is molded to a portion of the distal face 374. In one ormore embodiments, the porous portion 390 may be attached to the distalface 374 of the stopper by mechanical means, for example, adhesivesand/or molding. In a specific embodiment, the distal face 374 mayinclude a pocket (not shown) for securing the porous portion 390adjacent to the distal face 374 and the opening 376.

The stopper hub 350 includes an open distal end 351 and an open proximalend 359. The open distal end 351 includes a stopper-engaging portion352, which may include a disc extending radially outwardly, forattachment of the stopper hub 350 to the stopper 360. Specifically, asmore clearly shown in FIGS. 29A and 29B, the stopper-engaging portion352 extends radially outwardly to engage the peripheral channel 368 ofthe stopper 360. The stopper-engaging portion 352 may be in the form ofa tab (not shown), which corresponds to an opening or othercorresponding structure on the inside surface 364 of the stopper. In aspecific embodiment, the stopper-engaging portion 352 may have anopening and the inside surface of the stopper may include a tab (notshown) extending radially inwardly to engage with the opening (notshown). Other means to engage the stopper hub 350 to the stopper 360 mayalso be utilized. Alternatively, the stopper 360 may be integrallyformed on the distal end 351 of the stopper hub 350 or permanentlyattached to the distal end 351 of the stopper hub 350 using methods knowin the art. The stopper hub may be formed from a rigid plastic or othermaterial.

A boss 353 extends from the stopper-engaging portion 352 to aplunger-engaging portion 354 that is disposed adjacent to the openproximal end 359 of the stopper hub 350. A hollow spike 392 is attachedto the open proximal end 359 and extends from the boss 353 in a proximaldirection. The hollow spike 392 defines a space 396 in fluidcommunication with the conduit 355 and includes a piercing end 394. Thehollow spike 392 may be formed from a rigid plastic, metal or othermaterial suitable to pierce and penetrate the distal end 241 of theplunger rod 340 as will be described herein. The boss 353 includes ahollow interior in fluid communication with the open distal end 351 andthe open proximal end 359. As shown in FIGS. 27 and 28, the boss 353 hasa cylindrical shape with a conduit 355 that extends from the open distalend 351 to the hollow spike 392. The plunger-engaging portion 354includes an exterior surface 356 configured to frictionally engage theinside surface of the plunger rod 340, as will be described below. Asshown in FIG. 28, the plunger-engaging portion 354 includes an axiallength and a plurality of grooves 357 disposed along its axial length.Alternatively, the plunger-engaging portion 354 may have a texturedsurface or a coating (not shown) that creates or increases frictionalinterference between the exterior surface 356 of the plunger-engagingportion 354 and the inside surface of the plunger rod 340.Alternatively, the plunger rod 340 may be attached in a slidablerelationship with the plunger-engaging portion 354 of the stopper hub350 such that the plunger rod 340 slides proximally and distally overthe exterior surface 356 of the stopper hub 350.

During use, the plunger rod 340 is configured to be attached to theproximal end 359 of the stopper hub. The plunger rod shown more clearlyin FIGS. 29A and 29B includes a distal end 341, a proximal end 349, anda hollow elongate body 342 extending from the distal end 341 and theproximal end 349. The plunger rod 340 may be made of a rigid plastic orother material that has sufficient rigidity to withstand movement in theproximal and distal direction within the syringe barrel 310. Examples ofsuch materials include polypropylene, polyethylene, polycarbonate andcombinations thereof. The elongate body 342 may be cylindrical. In oneor more embodiments, the shape of the hollow elongate body 342 may berectangular or other shape. The proximal end 349 of the plunger rod 340includes an optional thumbpress 348.

The hollow elongate body 342 includes an inside surface 343 that definesa plunger rod cavity or a void space 344 having a vacuum. The distal end341 of the plunger rod includes a pierceable wall 345 or septum thatseals the vacuum within the void space 344 of the hollow elongate body342. The vacuum within the elongate body 342 may be formed prior toformation of the pierceable wall 345 by means known in the art. Theplunger rod 340 may include an interior plunger (not shown) disposedtelescopically within the elongate body 342, as will be described hereinwith reference to embodiments according to the seventh aspect of thepresent invention. The interior plunger (not shown) may be partiallywithdrawn from the elongate body to create a vacuum within the elongatebody 342.

As shown, the pierceable wall 345 is concavely shaped with respect tothe distal end 341 of the plunger rod. The pierceable wall 345accommodates the hollow spike 392 without allowing the hollow spike 392to pierce the pierceable wall 345. In one or more embodiments, thisconfiguration allows the plunger rod 340 to at least partially engagethe stopper hub 350 without penetrating the pierceable wall 345. In oneor more embodiments, the pierceable wall 345 is formed across the opendistal end 341, forming a perpendicular surface to the hollow elongatebody 342. The pierceable wall 345 is adhered to the distal end 341 ofthe plunger rod at the inside surface 343 of the elongate body 342. Thepierceable wall 345 may be formed from an elastomeric material and mayhave a uniform thickness that extends across the cross-sectional widthof the void space 344. In a specific embodiment, the thickness of thepierceable wall 345 may be modified to facilitate or to resistaccidental piercing of the pierceable wall 345. For example, thethickness of the pierceable wall 345 may be decreased at the point atwhich the piercing end 394 pierces the pierceable wall 345 to facilitatepenetration of the hollow spike 392. Alternatively, the thickness of thepierceable wall 345 may be increased at the point at which the piercingend 394 pierces the pierceable wall 345 to prevent accidentalpenetration of the pierceable wall 345.

In use, as shown in FIGS. 29A and 29B, the plunger rod 340, stopper hub350 and stopper 360 are inserted into the open proximal end 329 of thesyringe barrel 310. Before aspirating fluid into the chamber 318 of thesyringe barrel 310 or other container, the distal face 374 of thestopper 360 is positioned adjacent to the distal wall 312 of the syringebarrel 310, so that the air within the chamber 318 is minimized and isprimarily present in the tip 320 of the syringe barrel 310 or othercontainer.

In the assembled state, the stopper 360 and stopper hub 350 are fullyassembled with the stopper-engaging portion 352 engaged with theperipheral channel 368 of the stopper 360. The stopper hub 350 and theplunger rod 340 are engaged in a first position. In the first position,the plunger rod 340 and, specifically, the pierceable wall 345 arepositioned so that the piercing end 394 of the hollow spike 392 does notpenetrate completely through the pierceable wall 345 and the vacuumwithin the elongate body 342 remains intact. The plunger rod 340 isdisposed within the chamber 318 of the syringe barrel 310 so thepierceable wall 345 is positioned at a distance from the hollow spike392 as shown in FIGS. 29A and 29B. In a specific embodiment, thepierceable wall 345 may be positioned adjacent to the piercing end 394of the hollow spike 392 and the pierceable wall 345 and vacuum withinthe void space 344 remains intact. In a more specific embodiment, thepiercing end 394 may partially penetrate the pierceable wall 345, whileleaving the vacuum within the void space 344 intact. In these positions,the plunger-engaging portion 354 and the distal end 341 of the plungerrod may be engaged, partially engaged or disengaged. Engagement of thestopper hub 350 and the plunger rod 340 in the first position may befacilitated by the length of the plunger-engaging portion 354. Thelength of the plunger-engaging portion 354 or the position and shape ofthe pierceable wall 345 may allow full and/or partial engagement of thestopper hub 350 and the plunger rod 340 without penetration of thehollow spike 392 through the pierceable wall 345.

As shown in FIGS. 30 and 31, to fill the chamber 318 of the chamber 318of the syringe barrel 310 or other container, the needle cannula 384 isinserted into a container, such as a vial 50, to draw the fluid withinthe container into the syringe barrel 310. Thereafter, an initial forcein the distal direction is applied to the plunger rod 340 to engage thestopper hub 350 and plunger rod 340 from the first position to a secondposition. In the second position, the piercing end 394 of the hollowspike 392 fully penetrates the pierceable wall 345 and releases thevacuum contained within the void space 344 of the plunger rod.

When configured in the second position, the plunger-engaging portion 354engages the distal end 341 of the plunger rod to form a fluid-tight sealand fluid communication between the void space 344, conduit 355 andstopper cavity 366. The vacuum is released to the conduit 355 andstopper cavity 366 and draws air into the tip 320 and/or chamber 318 ofthe syringe barrel without any movement of the stopper 360, as shown inFIGS. 30 and 31. Liquid may also be drawn into the tip 320 and/orchamber 318 however, the porous portion 390 prevents the liquid fromentering the stopper cavity 366, as described above. As describedherein, the porous portion 390 may include a hydrophobic filter, aswellable polymer or a combination thereof. For example, when the porousportion 390 utilizes a swellable polymer, the openings present in theswellable polymer close upon contact with the liquid. In embodimentsutilize a porous portion 390 including a hydrophobic filter or membrane,the hydrophobic filter prevents liquid from permeating through theporous portion 390.

As the user aspirates the liquid from the vial 50 into the chamber 318of the syringe barrel 310 by applying a proximally directed force on theplunger rod 340 or, more specifically, the thumbpress 348, any airtrapped within the chamber 318 rises to the top of the aspirated liquidor between the liquid and the stopper 360, as shown in FIGS. 32-33. Theair continues to be drawn into the stopper 360 and stopper hub 350 and,in one or more embodiments, into the hollow spike 392, which deliversthe air into the void space 344 of the plunger rod, as shown moreclearly in FIGS. 32 and 33. As shown in FIG. 34, the desired amount ofliquid may be filled into the syringe barrel, without the presence ofair.

To expel the fluid, the stopper hub 350 and plunger rod 340 remainedengaged in the second position and move together in the distaldirection, with the stopper 360, as a user applies a force on theplunger rod 340 or thumbpress 348 in the distal direction. In one ormore embodiments that utilize a stopper 360 having a distal face 374that flexes, the application of a continuous and distally directed forceon the plunger rod 340 causes the distal face 374 to flex convexly asthe distal face 174 contacts the distal wall 312 of the syringe barrel310. In embodiments which utilize a stopper 360 having a convexly-shapeddistal face 374, the distal face 374 conforms more closely to the distalwall 312 upon contact with the distal wall 312. The convex shape of thedistal face 374 upon contact with the distal wall 312 expels even moreliquid from the syringe barrel 310.

FIGS. 35-45 illustrate a medical device 400 according to a fourth aspectof the invention. The medical device 400 includes a plunger rod 440 witha first stopper 447, a second stopper assembly 460 including an porousportion 490 and plug 450 to aspirate a liquid into a container, forexample a syringe barrel 410 and expel the aspirated liquid. Thisconfiguration may be utilized as a traditional dose syringe, where theuser aspirates and expel a desired amount of liquid in a single use, asshown in FIG. 37-41, and/or as a “fixed-dose” syringe, where a user mayaspirate and expel a fixed amount of liquid in a single use, as shown inFIGS. 42-45.

The medical device 400 includes a first stopper 447 disposed on aplunger rod 440 and a second stopper assembly 460 is attachable to theplunger rod. For illustration, the medical device 400 is shown in usewith a container in the form of a syringe barrel 410 with needle cannula484 attached thereto. The syringe barrel 410 includes an open proximalend 419 and a distal end 411 and a distal wall 412. A sidewall 414extends from the distal end 411 to the open proximal end 419 andincludes an interior surface 416 that defines a chamber 418 forretaining or holding fluids, which may include liquid medication and/orother liquids. The distal end 411 may also include a tip 420 having anopen passageway 422 therethrough in fluid communication with the chamber418. The needle cannula 484 is attached to the barrel 410 using a needlehub 480, which is attached to an optional luer fitting 488. The needlecannula 484 includes a lumen 486 or opening therethrough in fluidcommunication with the open passageway 422 and the chamber 418.Alternatively, the needle cannula 484 may be pre-attached directly tothe tip 420, using methods known in the art. The proximal end 419 of thesyringe barrel 410 includes an optional flange 424. The interior surface416 of the syringe barrel 410 may have a smooth surface that is free ofany protrusions or depressions. In use, second stopper assembly 460 isattached to a stopper-engaging portion 445 of the plunger rod 440, andthe assembled plunger rod and second stopper assembly 460 are insertedinto the open proximal end 419 of the syringe barrel 410.

As more clearly shown in FIG. 36, the second stopper assembly 460includes a distal end 461, an open proximal end 469 and a stopper body462 extending from the open distal end 461 to the open proximal end 469that includes an inside surface 464 defining a cavity 466. In one ormore embodiments, the inside surface 464 of the stopper body 462 mayinclude an attachment structure 468 for connecting the stopper body 462of the second stopper assembly 460 to the plunger rod 440. For example,the attachment structure 468 may include a depression or groove formedon the inside surface 464 of the stopper body 462 for engagement with acorresponding structure of the plunger rod 440. In one or moreembodiments, the attachment structure 468 may include a plurality ofgrooves (not shown) formed to grip the stopper-engaging portion 445 ofthe plunger rod when the stopper-engaging portion 445 is inserted intothe open proximal end 469 and into the cavity 466. Alternatively, theinside surface 464 is free of any structure and relies on a material,coating or texture to create or enhance the frictional interferencebetween the inside surface 464 and the plunger rod 440. For example, Asshown in FIG. 36, the stopper body 462 and/or inside surface 464, isformed from an elastomeric material, polymeric material or other knownmaterials, which may facilitate frictional engagement between the insidesurface 464 of the stopper body 462 and the plunger rod 440.

The stopper body 462 includes an outside surface 463 including a sealingportion 470. The sealing portion 470 is formed adjacent the distal end461. The sealing portion 470 may include one or more peripheral edges(not shown) that are shaped to form a fluid-tight seal with the interiorsurface 416 of a syringe barrel. In one or more embodiments, the sealingportion 470 may have a circular cross-section for forming a fluid-tightseal with a syringe barrel having an interior surface with a circularcross-section. The distal end 461 of the stopper body 462 includes aconvex distal face 472 having an opening 474 therethrough in fluidcommunication with the cavity 466. In one or more embodiments, thedistal face 472 may be flexible and can flex concavely and convexly. Thesealing portion 470 may be formed from a material suitable for forming afluid-tight seal with the interior surface 416 of the syringe barrel,which may include the same or different material utilized to form thestopper body 462.

The second stopper assembly 460 includes a plug 450 that is disposedwithin the cavity 466 of the stopper and extends partially through theopening 474 of the stopper body 462. As shown more clearly in FIGS.36-37, the plug 450 includes a distal end 451 and a proximal end 459,and an elongate core 452 extending from the distal end 451 to theproximal end 459. The plug 450 includes a head 454 at the proximal end459 of the elongate core 452. The length, shape and/or cross-sectionalwidth of the elongate core 452 permit the plug 450 to extend partiallythrough the opening 474 and permits movement of the plug 450 distallyand proximally through the opening 474. The length, shape and/orcross-sectional width of the head 454 prevent the plug 450 from fullyextending through the opening 474. In one or more embodiments, theelongate core 452 has a cross-sectional width that permits some liquidto enter the opening 474 to contact a porous portion 490 disposedbetween the head 454 and the opening 474. As shown, the head 454 is inthe form of a flat disc having a cross-sectional width larger than thecross-sectional width of the opening. Alternatively, the head 454 mayhave a square or rectangular shape to prevent the head from extendingthrough openings 474 having a circular shape.

The elongate core 452 includes a channel 456 extending from below thehead 454 and along a portion of the length of the elongate core 452.More specifically, the channel 456 extends from below the head 454 to apoint A along the length of the elongate core 452, wherein point A islocated between the distal end 451 of the elongate core 452 and the head454. In one or more embodiments, A is disposed at a midpoint along thelength of the elongate core 452. Alternatively, the elongate core 452includes a tapered end at the distal end 451 of the plug 450 and thepoint A is proximally adjacent to the tapered end distally adjacent tothe opening 474 to permit fluid communication between the chamber 418and the stopper cavity 466.

A porous portion 490 is disposed within the cavity 466 of the stopperbody 462 between at least a portion of the plug 450 and the insidesurface 464 of the stopper. The porous portion 490 is formed from aswellable polymer, as described herein. The porous portion 490 remainsin an unexpanded state and porous to air before contact with a liquid.Upon contact with a liquid, the porous portion 490 expands and becomesimpervious to air or liquid. Specifically, in one or more embodiments,the swellable polymer includes one or more openings that remain open toair flow but are closed due to the swellable polymer swelling uponcontact with a liquid, thereby preventing liquid from permeating throughthe porous portion 490. In one or more embodiments, the porous portion490 is disposed to form a buffer between the head 454 and the insidesurface 464 of the stopper body 462. In use, upon contact with a liquid,the expansion of the porous portion 490 moves the head 454 and the plug450 in the proximal direction, with respect to the opening 474 andinside surface 464 of the stopper. The presence of the porous portion490 between at least a portion of the plug 450 and the inside surface464 of the stopper, as shown in FIG. 37, blocks distal movement of theplug 450 relative to the opening 474 by forming a barrier between thehead 454 and the inside surface 464 of the stopper body 462. As shown inFIG. 34, the porous portion 490 may be cylindrically shape with a hollowinterior 492. The elongate core 452 of the plug 450 extends through thehollow interior 492. The length, shape and/or cross-sectional width ofthe porous portion 490 may be modified to any length, shape and/orcross-sectional width which permits the porous portion 490 to form abarrier between the head 454 and the inside surface 464 of the stopperand that is positioned to contact the liquid within the chamber 418. Ina specific embodiment, the porous portion 490 may be in the shape of atorus, a cylindrical shape or any other shape surrounding the channel456 and the elongate core 452. Alternatively, the porous portion 490 maybe integrally formed on the elongate core 452. In one or moreembodiments, the position and shape of the porous portion 490 may extendinto the channel 456 that is disposed along a portion of the length ofthe plug 450.

The expansion of the swellable polymer functions to move the plug 450proximally, by exerting a force in the proximal direction to the head454. When in an unexpanded state, the porous portion 490 is disposedbetween the head 454 and the inside surface 464 of the stopper body 462such that the channel 456 of the plug partially extends distally throughthe opening 474, permitting fluid communication between the chamber 418and the cavity 466. When in an expanded state, the porous portion isdisposed between the head 454 and the inside surface 464 of the stopperbody 462 such that the channel 456 does not extend through the opening474 and remains proximally adjacent to the opening 474. When the porousportion 490 is in the expanded state, the position of the channel 456prevents fluid communication between the chamber 418 and the cavity 466.In one or more embodiments, the elongate core 452 forms a fluid-tightseal with the opening 474 when the channel 456 is disposed proximallyadjacent to the opening 474.

The plunger rod 440 may be attached to the second stopper assembly 460.The plunger rod 440 shown more clearly in FIG. 35 includes a distal end441, a proximal end 449, and an elongate body 442 extending from thedistal end 441 and the proximal end 449 having a space 443. The space443 is shown to extend along the length of the elongate body 442,however, it may be of any size or dimension to provide a vent for theair evacuated from the needle hub 480, tip 420 and chamber 418 betweenthe second stopper assembly 460 and distal wall 412 of the syringebarrel.

The distal end 441 of the plunger rod shown in FIGS. 35-45 includes anoutlet 444 and a valve 494 that provide a vent for the air evacuatedfrom the syringe barrel 410 during use. The vent may be provided usingalternative structures, for example, the first stopper 447 may have theshape and structure to provide a resilient barrier to fluid flow betweenthe chamber 418 between the second stopper assembly 460 and the plungerrod 440 and the exterior of the syringe barrel 410 and the medicaldevice 400. For example, the first stopper 447 may provide a fluid-tightseal with the interior surface 416 of the syringe barrel 410 duringmovement of the plunger rod 440 in the proximal direction but releasesthe fluid-tight seal with the interior surface 416 of the syringe barrel410 during movement of the plunger rod 440 in the distal direction.

The outlet 444 and valve 494 permit fluid communication with the void443. The outlet 444, when sealed, facilitates the formation of a vacuumwithin the chamber 418 of the syringe barrel 410 between the secondstopper assembly 460 and the plunger rod 440. The valve 494 may be inform of any one-way valve or check valve that opens in one direction.

In one or more embodiments, the valve 494 provides a means for ventingthe air evacuated into the chamber 418 of the syringe barrel 410 betweenthe second stopper assembly 460 and the plunger rod 440. In a specificembodiment, the valve 494 provides a relief valve for the vacuum createdwithin the chamber 418, between the second stopper assembly 460 and theplunger rod 440, as will be explained in more detail below. In one ormore embodiments the distal end 441 of the plunger rod 440 does notinclude a valve 494 or an outlet 444. The air evacuated into the chamber418 remains within the space of the chamber 418 between the secondstopper assembly 460 and the plunger rod 440.

In one or more embodiments which incorporate a valve 494 and an outlet444, the valve 494 closes during creation of the vacuum within thechamber 418 between the second stopper assembly 460 and the plunger rod440 and seals the outlet 237. During when the plunger rod 440 isattached to the second stopper assembly 460, the valve 494 opens topermit the air contained within the chamber between the plunger rod 440and the second stopper assembly 460 escapes through the outlet 444. Inone or more embodiments, the valve 494 is in the form of a flap.

The plunger rod 440 may be made of a rigid plastic or other materialthat has sufficient rigidity to withstand movement in the proximal anddistal direction within the syringe barrel 410. Examples of suitablematerials include polypropylene, polyethylene, polycarbonate andcombinations thereof. The elongate body 442 may be cylindrical. In oneor more embodiments, the shape of the elongate body 442 may berectangular or other shape. The proximal end 449 of the plunger rod 440includes an optional thumbpress 448.

The distal end 441 of the plunger rod includes the stopper-engagingportion 445, mentioned above, for attaching the second stopper assembly460 to the distal end 441 of the plunger rod. In one or moreembodiments, the first stopper 447 is disposed between thestopper-engaging portion 445 and the elongate body 442, however, it maybe disposed at other locations on the plug 450. As shown, the firststopper is in the form of a disc formed around the elongate body 442,however, it may be attached as a separate component. The first stopper447 may be formed from a material suitable for forming a fluid-tightseal with the interior surface 416 of the syringe barrel, which mayinclude the same or different material utilized to form the stopper body462 and/or the sealing portion 470. Exemplary materials includeelastomeric materials, polymeric materials or other materials known inthe art.

As shown in FIGS. 35-44, the stopper-engaging portion 445 is shaped tofit within the cavity 466 of the stopper body 462. In one or moreembodiments, the stopper engaging portion 445 may includes a separateattachment structure. In a specific embodiment, the plunger rod 440 andsecond stopper assembly 460 may be attached after the plug 450 andporous portion 490 are disposed within the cavity 466, as will bediscussed below. As shown more clearly in FIG. 36, the stopper-engagingportion 445 includes a void 446 in fluid communication with the cavity466 of the stopper body 462, the channel 456 and the opening 474 of thestopper body. In one or more embodiments, the void 446 accommodatesmovement of the plug 450 in the proximal direction after expansion ofthe porous portion 490.

When utilizing medical device 400 in a traditional method, the plungerrod 440 and second stopper assembly 460 are inserted into the openproximal end 419 of the syringe barrel 410 but remain unattached. FIG.37 illustrates the medical device 400 assembled and positioned for useas a traditional dose syringe. In FIG. 37, the medical device 400 isinserted into the syringe barrel 410 with the distal face 472 of thesecond stopper assembly 460 adjacent to the distal wall 412 of thesyringe barrel and the plunger rod 440 is positioned at a short distancefrom the proximal end 269 of the second stopper assembly 460. Thechannel 456 is positioned so it extends through the opening 474 and is,at least partially, distally adjacent the opening 474 of the stopperbody 462.

The unattached plunger rod 440 and the second stopper assembly 460configuration permits the formation of a vacuum within the chamber 418between the second stopper assembly 460 and the plunger rod 440 byutilizing the first stopper 447 to form a fluid-tight seal with theinterior surface 416 of the syringe barrel 410 and moving the plungerrod 440 in the proximal direction relative to the separated andstationary second stopper assembly 460, which utilizes the sealingportion 470 to form a fluid-tight seal with the interior surface 416 ofthe syringe barrel.

FIGS. 37-40 illustrate a plunger rod 440 and second stopper assembly 460assembled within the chamber 418 prior to aspiration.

The second stopper assembly 460 and plunger rod 440 may be assembled inthe syringe barrel such that a vacuum may be created between the secondstopper assembly 460 and the plunger rod 440. This configuration may beutilized when using the medical device 400 with a syringe barrel as atraditional dose syringe or fixed-dose syringe. FIGS. 37-41 specificallyillustrate the use of the medical device 400 with a syringe barrel as atraditional dose syringe. The vacuum formed between the plunger rod 440and the second stopper assembly 460 drives the air through the channel465 and into the cavity 466.

As shown in FIG. 37, the second stopper assembly 460 may be disposedwithin the syringe barrel 410 such that the distal face 472 contacts thedistal wall 412 or is positioned as close as possible to the distal wall412. The plunger rod 440 is also disposed within the syringe barrel 410and remains unattached to the second stopper assembly 460. In thisconfiguration, the user may insert the needle cannula 484 into a vial 50and apply an initial force on the plunger rod 440 in the proximaldirection to cause the plunger rod 440 to move in the proximaldirection, while the second stopper assembly 460 remains stationary, asshown in FIG. 38. The first stopper 447 on the plunger rod 440 forms afluid tight seal with the inside surface 416 of the syringe barrel 410and movement of the first stopper 447 in the proximal direction causes avacuum to form between the second stopper assembly 460 and the plungerrod 440. The vacuum draws the valve 494 closed and prevents fluidcommunication between the chamber 418 and the space 443 of the plungerrod through the outlet 444.

As shown in FIG. 38, the air trapped within the needle hub 480 and thesyringe barrel 410 is drawn into the chamber 418 by the vacuum withinthe chamber 418 between the second stopper assembly 460 and the plungerrod 440. The vacuum also draws air into the channel 456, through theopening 474 of the stopper body 462 and into the stopper-engagingportion 445 of the plunger rod 440. The vacuum may also draw some liquidinto the chamber 418 before movement of the second stopper assembly 460,however, once the liquid contacts the porous portion 490, the porousportion 490 expands and exerts a force on the head 454 in the proximaldirection. This exertion of force causes the plug 450 to move proximallythrough the opening 474 into the cavity 466. Movement of the plug 450causes the channel 456 to be positioned proximally adjacent to theopening 474, permitting the elongate core 452 of the plug 450 to sealthe opening 474 of the second stopper or stopper assembly 460, therebycutting off or blocking any escape path for the liquid through thechannel 465. In this position, the elongate core 452 forms a fluid-tightengagement with the opening 474 of the stopper body, preventing anyliquid from entering the opening 474 and the cavity 466 of the stopperbody.

The user may aspirate a desired amount of liquid into the chamber 418 byattaching the plunger rod 440 to the second stopper assembly 460 andmoving the second stopper assembly 460 in the proximal direction. Theplunger rod 440 is attached to the second stopper assembly 460 uponapplication of a force on the plunger rod 440 in the distal direction sothe stopper-engaging portion 445 engages the attachment structure 468 ofthe second stopper assembly 460, as shown in FIG. 39. Movement of theplunger rod 440 in the distal direction causes the valve 494 to open andvents the air contained within the chamber 418 between the secondstopper assembly 460 and the plunger rod into the space 443 of theplunger rod. After attachment of the plunger rod 440 and the secondstopper assembly 460, the user may apply a force on the assembledplunger rod 440 and second stopper assembly 460 in the proximaldirection, as shown in FIG. 40. To expel the aspirated liquid, a forcemay be applied to the attached plunger rod 440 and second stopperassembly 460 in the distal direction until the desired amount of liquidis expelled from the chamber 418.

FIG. 42 illustrates the medical device 400 positioned for use as a fixeddose syringe. In FIG. 42, the medical device 400 is inserted into thesyringe barrel 410 with the distal face 472 of the second stopperassembly 460 positioned at a pre-determined distance from the distalwall 412 of the syringe barrel. The plunger rod 440 is unattached to thesecond stopper assembly 460 and the position of the stopper assembly 460at a distance from the distal wall 412 permits aspiration of apre-selected amount of liquid into the chamber 418 of the syringebarrel. As shown in FIG. 43, to fill the chamber 418 of the syringebarrel 410 or other container, the needle cannula 484 is inserted into acontainer, such as a vial 50, to draw the fluid within the containerinto the syringe barrel 410. Thereafter, the user applies a continuousforce in the proximal direction to the plunger rod 440 or, morespecifically, the thumbpress 448, to aspirate the desired amount ofliquid from the vial 50 into the syringe barrel 410. As shown in FIG.43, the plunger rod 440 is movable in the proximal and distal direction,independently of the second stopper assembly 460, which remainsstationary. The first stopper 447 forms a fluid-tight seal with thesyringe barrel and the movement of the plunger rod 440 in the proximaldirection forms a vacuum within the chamber 418. The vacuum draws thevalve 494 closed and prevents fluid communication between the chamber418 and the space 443 of the plunger rod 440 through the outlet 444.

The vacuum causes the air within the needle cannula 484 to be drawn intothe chamber 418. The air is evacuated into the second stopper assembly460 through the opening 474 and the channel 456 of the plug 450. Theopenings in the porous portion 490 remain open and permit air flow intothe stopper cavity 466. The vacuum also draws liquid into the chamber418. Any remaining air trapped within the needle hub 480 and the syringebarrel 410 rises to the top of the aspirated liquid or between theliquid and the distal face 472 of the stopper body 462.

As shown in FIG. 44, once the air contained within the syringe barrel410 escapes through the channel 456 and the aspirated liquid reaches theplug 450, the aspirated liquid also begins to enter the channel 456.Once the liquid contacts the porous portion 490, the porous portion 490expands and exerts a force on the head 454 in the proximal direction.The openings in the swellable polymer of the porous portion 490 closedue to swelling of the swellable polymer, forming a physical barrier toliquid flow. The exertion of force causes the plug 450 to moveproximally through the opening 474 into the cavity 466. Movement of theplug 450 causes the channel 456 to be positioned proximally adjacent tothe opening 474 and the elongate core 452 of the plug 450 forms afluid-tight seal with the opening 474, thereby cutting off or blockingany escape path for the liquid through the channel 465. In thisposition, as more clearly shown in FIG. 40, the elongate core 452 formsa fluid-tight engagement with the opening 474 of the stopper body,preventing any liquid from entering the opening 474 and the cavity 466of the stopper body.

To expel the liquid aspirated into the syringe barrel 410 in thefixed-dose configuration shown in FIGS. 42-45, the user may apply adistally directed force on the plunger rod 440 or thumbpress 448 tocause the plunger rod 440 to move in the distal direction. As theplunger rod 440 moves in the distal direction, the stopper-engagingportion 445 engages the inside surface 464 of the stopper body 462.During movement of the plunger rod 440 in the distal direction, thevalve 494 opens to permit fluid communication between the chamber 418and the space 443 of the plunger rod through the outlet 444.

Continuous application of a distally directed force causes the plungerrod 440 and second stopper assembly 460 move together in the distaldirection toward the distal wall 412 of the syringe barrel 410. Theporous portion 490 remains expanded and prevents movement of the plug450 in the distal direction, maintaining the position of the channel 456proximally adjacent the opening 474. This continuous force is applied tothe plunger rod 440 until the distal face 472 contacts the distal wall412 and the liquid is expelled or until the desired amount of liquid isexpelled.

FIGS. 46-55 illustrate a medical device 500 according to a fifth aspectof the invention. In one or more embodiments, the medical device 500includes a plunger rod 540 attached to a stopper hub 550 and a stopperassembly 560 including an actuated duct assembly 530 for aspiratingliquid into a container and expelling the aspirated liquid.

For illustration, the medical device 500 is shown in use with acontainer in the form a syringe barrel 510. As shown more clearly inFIGS. 46-55, the syringe barrel 510 includes an open proximal end 519, adistal end 511 and a distal wall 512. A sidewall 514 extends from thedistal end 511 to the open proximal end 519 and includes an interiorsurface 516 that defines a chamber 518 for retaining or holding fluids,which may include liquid medication and/or other liquids. The distal end511 may also include a tip 520 having an open passageway 522therethrough in fluid communication with the chamber 518. A needlecannula 584 is attached to the tip 520 and includes a lumen 586 oropening therethrough in fluid communication with the open passageway 522and the chamber 518. In the embodiments shown in FIG. 47, the needlecannula 584 is attached directly to the tip 220 using methods known inthe art. Alternatively, a needle hub (not shown) may be used to attachthe needle cannula 584 to the tip 520. The proximal end 519 of thesyringe barrel 510 may include optional flanges 524. The interiorsurface 516 of the syringe barrel 510 may have a smooth surface that isfree of any protrusions or depressions. In use, the plunger rod 540,stopper hub 550 and stopper assembly 560 are inserted into the openproximal end 519 of the syringe barrel 510.

As more clearly shown in FIG. 47, the stopper assembly 560 includes adistal end 561, an open proximal end 569 and a stopper body 562extending from the distal end 561 to the open proximal end 569. Thestopper body 562 includes an outside surface 563 and an inside surface564 defining a stopper cavity 566. In one or more embodiments, theinside surface 564 of the stopper body 562 may include a peripheralchannel 568 forming a groove or ridge within the body for engagementwith the stopper hub 550, as will be described in detail below. Thestopper body 562 also includes a sealing portion 570 formed on theoutside surface 563 for forming a fluid-tight seal with a syringe barrelhaving an interior surface with a circular cross-section. As shown inFIG. 46, the sealing portion 570 is formed adjacent the distal end 561,however, it may also be formed at other locations along the length ofthe outside surface 563 of the body 562. The sealing portion 570includes at least one peripheral edge 572 shaped to form a fluid-tightseal with the inside surface of a syringe barrel. In one or moreembodiments, the peripheral edge 572 may have a circular cross-sectionfor forming a fluid-tight seal with a syringe barrel having an interiorsurface with a circular cross-section.

The stopper assembly 560 may be formed from an elastomeric material,polymeric material or other material known in the art. In one or moreembodiments, the sealing portion 570 and/or the peripheral edge 572 maybe made from a material suitable for forming a fluid-tight seal with theinterior surface 516 of the syringe barrel 510 and may include the sameor different material than the remaining components of the stopperassembly 560.

As more clearly shown in FIG. 49, the distal end 561 of the stopperassembly 560 includes a distal face 574. In one or more embodiments, thedistal face 574 is pierceable, as will be described in more detailbelow. Alternatively, the distal face 574 includes an opening in fluidcommunication with the stopper cavity 566. The distal face 574 may havea convex shape or be flexible to flex to a convex shape which conformsto the distal wall 512 of the syringe barrel 510. In one or moreembodiments, the distal face 574 may also be shaped convexly so that itconforms more closely to the shape of the distal wall 512 of the syringebarrel 510 to expel as much liquid from the chamber 518 as possible. Thedistal face 574 may be formed from a material that reforms a fluid tightseal after being pierced. For example, the distal face 574 may be formedfrom a material that permits the distal face 574 to function as aseptum.

The stopper assembly 560 includes an actuated duct assembly 530 that isdisposed within the stopper cavity 566 and may be positioned to extendpartially through the distal face 574 of the stopper body 562. Theactuated duct assembly 530 includes a base 531 having a distal end 532and a proximal end 533. The distal end 532 of the base 531 includes aduct member 534 attached thereto that extends in the distal directionfrom the distal end 532 of the base 531. In one or more embodiments, theduct member 534 has a structure for piercing the distal face 574 of thestopper to form an opening and extends through the opening.Alternatively, the duct member 534 extends through a pre-formed openingin the distal face 574.

The length, shape and/or cross-sectional width of the base 531 preventthe actuator duct assembly 530 and, specifically, the base 531, fromextending completely through the distal face 574. As shown, the base 531has a circular cross-section having a cross-sectional width larger thanthe cross-sectional width of the opening created in the distal face 574by the duct member 534 or an opening preformed in the distal face.Alternatively, the base 531 may have a square or rectangularcross-section to prevent the actuator duct assembly 530 from extendingthrough a circular opening created in the distal face 574 by the ductmember 534 or a circular opening preformed in the distal face 574. Thebase 531 shown in FIG. 47 has a cylindrical shape or any other shape tofacilitate movement of the base 531 in the proximal direction. Forexample, the base 531 may be shaped to fit within the stopper hub 550and the hollow member 553 of the stopper hub 550. In one or moreembodiments, the base 531 may have other shapes, for example, the base531 may be shaped to include a flat disc (not shown) that is attached tothe duct member 534.

The duct member 534 includes a closed proximal end 536 attached to thedistal end 532 of the base 531, an open distal end 535 and a tubularwall 539 defining a channel 538 that extends from the closed proximalend 536 to the open distal end 535. The tubular wall 539 includes anopen lateral opening 537 adjacent to the closed proximal end 536 influid communication with the open distal end 535. When the medicaldevice 500 is assembled, the lateral opening 537 permits fluidcommunication between the open distal end 535 and the stopper cavity566. As shown in FIG. 47, the lateral opening 537 extends partiallyalong the length of the duct member 534 from the distal end of thetubular wall 539 such that the channel 538 is enclosed adjacent to theopen distal end 535 and partially enclosed adjacent to the lateralopening 537. As shown more clearly in FIG. 47, the lateral opening 537may be in the form of a notch or cut out in the tubular wall 539.

The open distal end 535 of the duct member 534 shown in FIG. 47 includesa beveled edge, however, a straight edge may also be utilized. The edgeof the open distal end 535 is utilized to pierce through the distal face574, allowing the tubular wall 539 to extend through the opening formedin the distal face 574. The open distal end 535 also permits fluidcommunication between the chamber 518 and the channel 538 of the ductmember 534. The length, shape and/or cross-sectional width of the ductmember 534 permit the actuated duct assembly 530 to extend through theopen distal end 551 of the stopper hub 550 and partially through theopening formed in the distal face 574 of the stopper body 562. Thelength, shape and/or cross-sectional width of the duct member 534 alsopermit movement of the actuator duct assembly 530 and, morespecifically, the base 531 in the distal and proximal directionsrelative to the distal face 574.

The actuated duct assembly 530 also includes a porous portion 590 havinga distal end 591, a proximal end 599 and a core 592 extending from thedistal end 591 to the proximal end 599. The porous portion 590 is formedfrom a swellable polymer, as described above. The porous portion 590remains in an unexpanded state and porous to air before contacting aliquid. Upon contact with a liquid, the porous portion 590 expands andbecomes impervious to air and/or liquid. Specifically, in one or moreembodiments, the swellable polymer includes one or more openings thatremain open to air flow prior to contact with a liquid but are closeddue to the swellable polymer swelling upon contact with a liquid,thereby preventing liquid from permeating through the porous portion590. In one or more embodiments, the porous portion 590 is disposedwithin the stopper cavity 566, adjacent to the duct member 534. In oneor more embodiments, the porous portion 590 is disposed to form a bufferor barrier between the base 531 and the inside surface 564 of thestopper body 562. The presence of the porous portion 590 between atleast ha portion of the base 531 and the inside surface 564 of thestopper, as shown in FIG. 49, blocks distal movement of the base 531relative to the distal face 574 by forming a barrier between the base531 and the inside surface 564 of the stopper body 562. In use, uponcontact with a liquid, the expansion of the porous portion 590 moves thebase 531 and duct member 534 in the proximal direction, with respect tothe inside surface 564 of the stopper.

The length, shape and/or cross-sectional width of the porous portion 590may be modified to any length, shape and/or cross-sectional width whichpermits the porous portion 490 to form a barrier between the base 531and the inside surface 564 of the stopper and that is positioned tocontact the liquid within the chamber 518. In a specific embodiment, theporous portion 590 may be in the shape of a torus or may have acylindrical shape or any other shape to surround the lateral opening 537and prevent liquid from flowing between the lateral opening 537 and thestopper cavity 566. Alternatively, the porous portion 590 may beintegrally formed on the duct member 534. In one or more embodiments,the position and shape of the porous portion 590 may extend into thelateral opening 537 that is disposed along a portion of the length ofthe duct member 534.

As shown in FIG. 49, the duct member 534 and the porous portion 590 areengaged such that the duct member 534 extends through the core 592 ofthe porous portion 590. As shown, the open distal end 535 of the ductmember extends through the core 592 and past the distal end 591 of theporous portion 590. According to one or more embodiments, the ductmember 534 is engaged with the porous portion 590 by using the opendistal end 535 of the duct member 534 to pierce the core 592 at theproximal end 599 and through to the distal end 591 of the core 592 sothe open distal end 535 extends past the distal end 591 of the core, asshown in FIG. 48. In one or more embodiments, the core 592 forms afluid-tight seal with the duct member 534 after swelling or activationbut and permits fluid communication between the chamber 518 and thestopper cavity 566 before swelling or activation. In one or morealternative embodiments, the porous portion 590 includes an inlet (notshown) at the proximal end 599 and an outlet (not shown) at the distalend 591 that define a path (not shown) through the porous portion 590.In such embodiments, the duct member 534 is inserted through the inletand extends past the outlet. The path may have a size and length, shapeand/or cross-sectional width to form a fluid-tight seal with the tubularwall 539 of the duct member 534.

The actuator duct assembly 530 is positioned with respect to the porousportion 590 such that the expansion of the swellable polymer functionsto move the base 531 in the proximal direction, by exerting a force onthe distal end 532 of the base 531 in the proximal direction. When in anunexpanded state, the porous portion 590 is disposed between the distalend 532 of the base 531 and the inside surface 564 of the stopper body562 such that the duct member 434 partially extends distally through thedistal face 574. In the unexpanded state, as shown in FIGS. 48-49, theopen distal end 535 of the duct member 534 extends distally past thedistal face 574. The lateral opening 537 remains disposed proximallyadjacent to the distal face 574. In one or more embodiments, the lateralopening 537 may be partially or completely surrounded by the porousportion 590. In the event the lateral opening 537 is partially orcompletely surrounded by the porous portion 590, expansion of the porousportion may close or seal the lateral opening 537 upon contact with aliquid and prevent fluid communication between the lateral opening 537and the open distal end. The expansion of the porous portion 590 causesthe base 531, duct member 534 and, consequently, the open distal end 535to move proximally relative to the distal face 574. The movement of theduct member 534 causes the open distal end 535 of the duct member 534 tobe enclosed within the stopper cavity 566 and disposed proximallyadjacent the distal face 574. The distal face 574 reforms a fluid-tightseal to prevent communication between the stopper cavity 566 and thechamber 518. The positioning of the open distal end 535 proximallyadjacent the distal face 574 and enclosed within the stopper cavity 566prevents fluid communication between the stopper cavity and chamber 518.In one or more embodiments, the movement of the duct member 534 may alsocause the lateral opening 537 to be completely surrounded by the porousportion 590, which is rendered impervious to air and liquid upon contactwith a liquid. In such embodiments, fluid communication between thestopper cavity 566 and chamber 518 is further prevented by the sealformed around the lateral opening 537.

As shown in FIGS. 46-48, the stopper hub 550 is attached to the proximalend 569 of the stopper body. The stopper hub 550 includes an open distalend 551 and an open proximal end 559. The open distal end 551 of thestopper hub 550 provides a support on which the base 531 of the actuatedduct assembly 530 rests. The duct member 534 extends through the opendistal end 551.

The stopper hub 550 also includes a stopper-engaging portion 552, whichmay include a disc extending radially outwardly, for attachment of thestopper hub 550 to the stopper assembly 560. Specifically, as moreclearly shown in FIG. 48, the stopper-engaging portion 552 is disposedat the distal end 551 of the stopper hub 550 and extends radiallyoutwardly to engage the peripheral channel 568 of the stopper assembly560. In one or more embodiments, the stopper-engaging portion 552 may bein the form of a tab (not shown), which corresponds to an opening orother corresponding structure on the inside surface 564 of the stopper.In a specific embodiment, the stopper-engaging portion 552 may have anopening (not shown) and the inside surface of the stopper may include atab (not shown) extending radially inwardly to engage with the opening(not shown). Other means to engage the stopper hub 550 to the stopperassembly 560 may also be utilized. Alternatively, the stopper assembly560 may be integrally formed on the distal end 551 of the stopper hub550. The stopper hub may be formed from a rigid plastic or othermaterial.

A hollow member 553 extends from the stopper-engaging portion 552 to aplunger-engaging portion 554, disposed adjacent to the proximal end 559of the stopper hub 550. As shown, the plunger-engaging portion 554 isformed on the outside surface of the hollow member 553. In one or morealternative embodiments, the plunger-engaging portion 554 may be formedon the inside surface of the hollow member 553. As shown in FIG. 47, theplunger-engaging portion 554 includes a plurality of projecting fingers555 extending from the hollow member 553 toward the proximal end 559. Inone or more embodiments, the plurality of projecting fingers 555 areconfigured to frictionally engage the inside surface of the plunger rod,as will be described below. As shown in FIG. 47, one or more of theprojecting finger 555 may include a support member 556 formed along theoutside surface of the hollow member 553. The support members 556 extendradially outwardly from the outside surface of the hollow member 553. Asshown in FIG. 47, the support members 556 have a rectangularcross-section, however, the support members 556 may have other shapes.The projecting fingers 555 extend in the proximal direction from thesupport members 556. As shown in FIG. 47, the projecting fingers 555include a notched portion 557 forming a hooked portion 558 facingradially outwardly. The hooked portion 558 may include a tapered surface587 that facilitates movement of the plunger rod 540 in the distaldirection relative to the stopper hub 550 to facilitate engagement ofthe plunger rod 540 and the stopper hub 550. When assembled to a plungerrod, the hooked portions 558 engage with a corresponding structureformed on the plunger rod 540 as will be described in additional detailbelow. Alternatively, the plunger-engaging portion 554 may be formed onthe outside surface of the hollow member 553 and may include a wall (notshown) having a groove (not shown) formed on the wall for engagementwith a corresponding structure on the plunger rod. In one or moreembodiments, the plunger-engaging portion 554 may include a wall (notshown) having a textured surface or a coating that creates or increasesfrictional interference between the exterior surface of theplunger-engaging portion 554 and the inside surface of the plunger rod.The plunger rod 540 and the stopper hub may also be attached using othermeans known in the art.

The plunger rod shown more clearly in FIGS. 46 and 48 includes an opendistal end 541, a proximal end 549, and a hollow elongate body 542extending from the distal end 541 and the proximal end 549. The hollowelongate body 542 includes an inside surface 543 that defines a voidspace 544 and an outside surface 546 including a sealing edge 547. Thesealing edge 547 forms fluid-tight seal with the interior surface 516 ofthe syringe barrel 510 and may be formed from an elastomeric material,polymeric material or other known material suitable for forming afluid-tight seal with the interior surface 516 of the syringe barrel.The plunger rod 540 may be made of a rigid plastic or other materialthat has sufficient rigidity to withstand movement in the proximal anddistal direction within the syringe barrel 510. Examples of suchmaterials include polypropylene, polyethylene, polycarbonate andcombinations thereof. The elongate body 542 may be cylindrical. In oneor more embodiments, the shape of the elongate body 542 may berectangular or other shape. The proximal end 549 of the plunger rod 540includes an optional thumbpress 548.

The inside surface 543 of the plunger rod 540 includes an engaging meansfor engaging the plunger-engaging portion 554 of the stopper hub 550. Asshown in FIG. 48, the engaging means includes a peripheral groove 545disposed adjacent to the open distal end for engaging the hooked portion558 of the projecting fingers 555.

In use, the stopper hub 550 is engaged to the stopper assembly 560 anddisposed within the chamber 518 of the syringe barrel 510. The plungerrod 540 is inserted into the syringe barrel 510 and remains unattachedto the plunger-engaging portion 554 of the stopper hub 550. During use,the plunger rod 540 may be engaged to the stopper hub 550, as shown inFIGS. 48-55. Before aspirating fluid into the chamber 518 of the syringebarrel 510 or other container, the distal face 574 of the stopperassembly 560 is positioned adjacent to the distal wall 528 of thesyringe barrel 510, so that the air within the chamber 518 is minimizedand is primarily present in the tip 520 of the syringe barrel 510 orother container. The open distal end 535 pierces the distal face 574 or,alternatively, extends through a preformed opening in the distal face574 to permit fluid communication between the chamber 518 and thestopper cavity 566. In one or more embodiments, the distal face 574forms a fluid tight seal with the tubular wall 539 of the duct member534. The plunger rod 540 is positioned unattached to theplunger-engaging portion 554 of the stopper hub 550 in a first position,as shown more clearly in FIG. 49. In the first position, the plunger rod540 is not engaged with the stopper hub 550 and is moveable in theproximal and distal directions within the chamber 518, independently ofthe stopper assembly 560 and/or stopper hub 550. In one or moreembodiments, the open distal end 541 of the plunger rod is positionedadjacent to the tapered surface 587 of the hooked portion 558 of theprojecting fingers 555 but not engaged with the notched portion 557 ofthe plunger-engaging portion 554.

As shown in FIG. 50, to fill the chamber 518 of the syringe barrel 510or other container, the needle cannula 584 is inserted into a container,such as a vial 50, to draw the fluid within the container into thesyringe barrel 510. A force in the proximal direction is applied to theplunger rod 540 while the plunger rod 540 is positioned in the firstposition. The sealing edge 547 forms a fluid-tight seal with theinterior surface 516 of the syringe barrel as the plunger rod is pulledor moved in the proximal direction. The movement of the plunger rod 540also creates a vacuum within the chamber 518 between the stopper hub 550and the plunger rod 540. The vacuum causes a pressure differentialbetween area within the tip 520 and chamber 518 between tip 520 and thedistal face 574 of the stopper body 562 and the area within the chamber518 between inside surface 564 of the stopper body 562 and the insidesurface 543 of the plunger rod 540. The pressure differentialfacilitates evacuation of air trapped within the needle cannula 584, tip520 and chamber 518 through the open distal end 535 and lateral opening537 of the duct member 534. In one or more embodiments, the air isevacuated through the porous portion 590, which remains porous to airbecause liquid has not yet entered the duct member 534. The air escapesthrough the porous portion 590 through the hollow member 553 of thestopper hub 550 and into the chamber formed between the stopper hub 550and the plunger rod 540. The evacuation of air from the syringe barrel510 and tip 520 is shown more clearly in FIGS. 50-51.

As air begins to escape through the duct member 534, the vacuum withinthe chamber 518 between the inside surface 564 of the stopper assembly560 and the inside surface 543 of the plunger rod may also draw liquidinto the chamber 518 of the syringe barrel 510. As the liquid enters theduct member 534 and flows through the lateral opening 537, it comes incontact with the porous portion 590. Upon contact with the liquid, theswellable polymer of the porous portion 590 begins to expand and theopenings in the porous portion 590 begin to close. The expansion of theporous portion 590 causes a force in the proximal direction to beapplied to the distal end 532 of the base 531. This force causes thebase 531 to move in the proximal direction, relative to the distal face574 of the stopper body 562. This movement also causes the open distalend 535 of the duct member 534 to move in the proximal direction so itis proximally adjacent to the distal face 574. The distal face 574 ofthe stopper reforms a fluid tight seal, preventing fluid communicationbetween the chamber 518 and the stopper cavity 566. In one or moreembodiments, the porous portion may also seal or close the lateralopening 537 to further prevents fluid communication between the chamber518 and stopper cavity 566.

Thereafter, a force in the distal direction is applied to the plungerrod to engage the stopper hub 550 and plunger rod 540 from the firstposition to a second position to aspirate a desired amount of liquidinto the chamber 518. In the second position, the projecting hookedportion 558 of the projecting finger 555 engages the peripheral groove545 of the plunger rod, as shown in FIG. 54. When engaged, the plungerrod 540, stopper hub 550 and the stopper assembly 560 are moveable inthe proximal and distal direction within the chamber 518 of the syringebarrel 510, as a unit.

As the user aspirates the liquid from the vial 50 into the syringebarrel 510 by applying a proximally directed force on the plunger rod540 or, more specifically, the thumbpress 548, the stopper assembly 560,stopper hub 550 and plunger rod 540 move in the proximal directiontogether and the liquid is filled into the chamber 518 of the syringebarrel, as shown more clearly in FIG. 55. The position of the opendistal end 535 within the stopper cavity 566 590 prevents liquid fromentering the stopper cavity 566. As shown in FIG. 55, the desired amountof liquid may be filled into the syringe barrel, without the presence ofair.

To expel the fluid, the stopper assembly 560, stopper hub 550 andplunger rod 540 remained engaged in the second position and movetogether in the distal direction, as a user applies a force on theplunger rod 540 or thumbpress 548 in the distal direction. In one ormore embodiments that utilize a stopper assembly 560 having a distalface 574 that is flexible, the application of a continuous and distallydirected force on the plunger rod 540 causes the distal face 574 to flexconvexly as the distal face contacts the distal wall 512 of the syringebarrel 510. In embodiments which utilize a stopper assembly 560 having aconvexly-shaped distal face 354, the distal face 574 conforms moreclosely to the distal wall 512 upon contact with the distal wall 512.The convex shape of the distal face 574 upon contact with the distalwall 512 expels even more liquid from the syringe barrel 510.

A medical device 600 according to a sixth aspect of the presentinvention is shown in FIGS. 56-67. One or more embodiments of themedical device 600 includes a plunger rod 640, a stopper 660 and astopper hub 650, wherein a distal end 641 of the plunger rod 640 andstopper hub 650 are slidably engaged to allow the user to create avacuum between the stopper hub 650 and plunger rod 640. Forillustration, the medical device 600 is shown in use with a container inthe form a syringe barrel 610. The syringe barrel 610 includes an openproximal end 619, a distal end 611 and a distal wall 612. As moreclearly shown in FIGS. 61-62, a sidewall 614 extends from the distal end611 to the open proximal end 619 and includes an interior surface 616that defines a chamber 618 for retaining or holding fluids, which mayinclude liquid medication and/or other liquids. The distal end 611 alsoincludes a tip 620 having an open passageway 622 therethrough in fluidcommunication with the chamber 618. The open proximal end 519 of thesyringe barrel 510 may include optional flanges 624. A needle cannula684 is attached to the tip 620 and includes a lumen 686 or openingtherethrough in fluid communication with the open passageway 622 and thechamber 618. In the embodiments shown in FIGS. 56-67, the needle cannula684 is attached directly to the tip 620 using methods known in the art.Alternatively, a needle hub (not shown) may be used to attach a needleto the tip 620. The interior surface 616 of the syringe barrel 610 mayhave a smooth surface that is free of any protrusions or depressions. Inuse, the plunger rod 640, stopper hub 650 and stopper 660 are insertedinto the open proximal end 629 of the syringe barrel 610.

As more clearly shown in FIGS. 57 and 59, the stopper 660 includes adistal end 661 and an open proximal end 669 and a body 662 extendingfrom the distal end 661 to the open proximal end 669. The body 662includes an outside surface 663 and an inside surface 664 defining astopper cavity 666. In one or more embodiments, the inside surface 664of the body 662 may include a peripheral channel 668 forming a groove orridge, within the body 662 for engagement with the stopper hub 650, aswill be described in detail below and is shown more clearly in FIG. 61.As shown in FIGS. 57 and 59, the body 662 includes a sealing portion 670for forming a fluid-tight seal with the interior surface 616 of asyringe barrel. As shown, the sealing portion 670 is disposed on theoutside surface 663 adjacent the distal end 661. In one or moreembodiments, the sealing portion 670 may includes one or more grooves(not shown) shaped to form a fluid-tight seal with the interior surface616 of a syringe barrel. In one or more embodiments, the sealing portion670 may have a circular cross-section for forming a fluid-tight sealwith a syringe barrel having an interior surface with a circularcross-section. The stopper 660 may be formed from an elastomericmaterial, polymeric material or other material known in the art. In oneor more embodiments, the sealing portion 670 may be formed from amaterial suitable for forming a fluid-tight seal with the interiorsurface 616 of the syringe barrel 610, which may include the same ordifferent material utilized to form the remaining components of thestopper 660.

The distal end 661 of the stopper 660 includes a distal face 672 havingan opening 674 therethrough in fluid communication with the stoppercavity 666. The distal end 661 also includes a path 676 extending fromthe opening 674 to the stopper cavity 666 allowing fluid communicationfrom the opening 674 to the open proximal end 669. The distal face 672may have a convex shape or be flexible to flex to a convex shape whichconforms to the distal wall 612 of the syringe barrel 610. In one ormore embodiments, the distal face 672 may also be shaped convexly sothat it conforms more closely to the shape of the distal wall 612 of thesyringe barrel 610 to expel as much liquid from the chamber 618 aspossible.

As shown in FIGS. 57-59, a filter 690 is disposed in the stopper cavity666 adjacent to the distal face 672. As shown, the filter 690 has ashape and size to cover the opening 674, the path 676 and surroundingportions of the inside surface 664 of the body 662 of the stopper. Inone or more embodiments, the filter 690 is shaped to cover the opening674 and the path 676, but not any portions of the inside surface 664surrounding the opening 674 or path 676.

As shown in FIGS. 58A and 58B, the filter 690 includes a porous portion691 formed from a hydrophobic filter, swellable polymer or combinationsthereof. The porous portion 691 as shown in FIG. 57 has across-sectional width to permit the porous portion 691 to cover or bedisposed within the opening 674. A barrier wall 692 surrounds the porousportion 691 and extends in the proximal direction, perpendicularly tothe porous portion 691. As shown, the filter 690 includes a shieldportion 693 disposed around the barrier wall 692 and extending radiallyoutwardly from the barrier wall 692. In one or more embodiments, thebarrier wall 692 may have a length long enough to permit the porousportion 691 to be positioned within the opening 674 and the shieldportion 693 to be disposed adjacent to the inside surface 664 of thestopper 660 at the distal face 672, as shown in FIG. 59. In one or moreembodiments, the barrier and shield may be solid or may be porous. Inembodiments where the barrier and/or shield are porous, the barrierand/or shield may be formed from a hydrophobic filter, a swellablepolymer or combinations thereof.

The filter 690 may be a separate component that is inserted and attachedwithin the path 676, adjacent the opening 674. In one or moreembodiments, the filter 690 may include only the porous portion 691 andno barrier wall 692 or shield portion 693. In a specific embodiment, thefilter 690 may include the porous portion 691 and the barrier wall 692but no shield portion 693. In an even more specific embodiment, thefilter 690 may include the porous portion 691 and the shield portion 693but no barrier wall 692. In one or more embodiments, the filter 690 maybe integrally formed on the distal face 672, with the peripheral edgesof the distal face 672 and the sealing portion 670 of the stopper 660remaining non-porous. As shown FIG. 58A and FIG. 58B, the porous portion691 is formed from a swellable polymer, as described above. The porousportion 691 may include a plurality of apertures 694 or holes that allowfluid communication of air through the openings. In one or moreembodiments, the swellable polymer expands upon contact with a liquidand causes the plurality of to close. Accordingly, in such embodiments,air contained within the syringe barrel is permitted to escape throughthe plurality of apertures 694 prior to contact between the swellablepolymer and liquid. Upon contact with a liquid, the plurality ofapertures 694 of the swellable polymer close and no fluid is permittedto enter the plurality of apertures 694 or escape from the chamber 618.

Alternatively, the porous portion 691 may be provided as a separatecomponent and may be disposed in the path 676 and/or opening 674 and influid communication with the path 676, stopper cavity 666 and theopening 674. In one or more embodiments, the porous portion 691 has acircular shape. Alternatively, the porous portion 691 may have a squareand/or rectangular shape. The porous portion 691 may be integrallyformed or disposed on the distal face 672, adjacent to the opening 674.In a specific embodiment, the porous portion has a cross-sectional widththat is smaller than the cross-sectional width of the distal face 672.The porous portion may also be integrally formed and/or disposedadjacent to the path 676 on the inside surface 664 of the stopper. Theporous portion 691 may have a cross-sectional with that is smaller thanthe cross-sectional width of the inside surface 664 of the stopper.

The porous portion 691 may be integrally formed on the distal face 672,with the peripheral edges of the distal face 672 and the sealing portion670 remaining non-porous. In a specific embodiment, the porous portion691 is separated from the sealing portion 670 by the distal face 672.

The porous portion 691 may also be shaped to fit within the opening 674and form a fluid-tight engagement with the opening 674. For example, theporous portion 691 may extend from the distal face 672 into the path676. In one or more embodiments, the porous portion 691 may have aperiphery that is molded to a portion of the distal face 672. In one ormore embodiments, the porous portion 691 may be attached to the distalface 672 of the stopper 660 by mechanical means, for example, adhesivesand/or molding. In a specific embodiment, the distal face 672 mayinclude a pocket (not shown) for securing the porous portion 691adjacent to the distal face 672 and the opening 674.

The stopper hub 650 includes an open distal end 651 and an open proximalend 659. The open distal end 651 includes a stopper-engaging portion652, which may include a disc extending radially outwardly, forattachment of the stopper hub 650 to the stopper 660. Specifically, asmore clearly shown in FIG. 61, the stopper-engaging portion 652 extendsradially outwardly to engage the peripheral channel 668 of the stopper660. In one or more embodiments, the stopper-engaging portion 652 may bein the form of a tab (not shown), which corresponds to an opening (notshown) or other corresponding structure on the inside surface 664 of thestopper. In a specific embodiment, the stopper-engaging portion 652 mayhave an opening (not shown) and the inside surface of the stopper mayinclude a tab (not shown) extending radially inwardly to engage with theopening (not shown). Other means to engage the stopper hub 650 to thestopper 660 may also be utilized. In one or more alternativeembodiments, the stopper 660 may be integrally formed on the distal end651 of the stopper hub 650.

The stopper hub 650 includes a peripheral wall 653 extending from theopen distal end 651 to the open proximal end 659. The peripheral wall653 includes an inside surface 654 defining a hub cavity 655 in fluidcommunication with the opening 674 and the stopper cavity 666. The hubcavity 655 has a volume that varies as position of the plunger rod 640with respect to the stopper hub 650 changes, as will be discussed belowin greater detail.

In one or more embodiments, the peripheral wall 653 includes aplunger-engaging portion 656 for attaching the stopper hub 650 to theplunger rod 640 in a slidable relationship or to allow the plunger rod640 to move proximally and distally relative to the stopper hub 650. Theslidable relationship between the plunger rod 640 and stopper hub 650forms a vacuum within the hub cavity 655. The plunger-engaging portion656 may include a structure formed on the peripheral wall 653 thatprevents separation of the plunger rod 640 and stopper hub 650. As shownin FIGS. 56-67, the inside surface 654 of the peripheral wall 653 has alength, shape and/or cross-sectional width that forms a fluid tight sealwith the distal end 641 of the plunger rod 640. The plunger-engagingportion 656 may include a textured surface or coating disposed on theinside surface 654 of the stopper hub 650 to increase the frictionalinterference between the plunger rod 640 and the inside surface 654 toprevent disengagement. Other examples of such structures includedepression (not shown) formed along the inside surface of the peripheralwall 653 for engaging a corresponding protrusion (not shown) on theplunger rod 640, wherein the depression is sized to allow proximal anddistal movement of the plunger rod 640 relative to the stopper hub 650but prevent separation of the plunger rod 640 from the stopper hub 650.

In one embodiment, the plunger-engaging portion 656 includes means forprevent movement of the plunger rod 640 in a distal direction relativeto the stopper hub 650, after an initial movement of the plunger rod 640in the proximal direction relative to the stopper hub 650. In otherwords, the plunger-engaging portion 656 includes means for maintaining avacuum within the hub cavity 655 formed from movement of the plunger rod640 in the proximal direction relative to the stopper hub 650. As shownin FIG. 60, the means for maintaining a vacuum may include a ridge 657formed on the inside surface 654. As shown, the ridge 657 engages thedistal end 641 of the plunger rod 640, as will be discussed below inmore detail and includes a stop face disposed between the ridge 657 andthe open proximal end 659 of the stopper hub 650. The stop face 658forms a barrier to block movement of the plunger rod 640 in the distaldirection, once it has moved in the proximal direction past the stopface 658, as will also be discussed in more detail below. Theplunger-engaging portion 656 also includes a means for preventingdisengagement of the plunger rod 640 and the stopper hub 650. In theembodiment shown, the plunger-engaging portion 656 is shown in the formof a raised ridge formed on the periphery of the inside surface 654 ofthe stopper hub 650 adjacent to the open proximal end 659. The raisedridge may be formed at interrupted intervals along the periphery of theinside surface 654 of the stopper hub adjacent to the open proximal end659. In one or more embodiments, the inside surface 654 of theperipheral wall 653 may include one or more tabs (not shown) adjacentthe open proximal end 659 to prevent disengagement of the plunger rod640 during movement in the proximal direction relative to the stopperhub 650. Alternatively, the frictional engagement between the insidesurface 654 of the stopper hub 650 and the distal end 641 of the plungerrod 640 prevents separation of the plunger rod 640 and the stopper hub650.

In the embodiment shown, the peripheral wall 653 includes at least onevent 685 disposed along its length. The at least one vent 685 is influid communication with the exterior of the syringe barrel 610 andplunger rod 640. As shown more clearly in FIGS. 61 and 64, the plungerrod 640 does not form a fluid-tight seal with the interior surface 616of the syringe barrel 610, thereby permitting fluid communicationbetween the at least one vent 685, the hub cavity 655 and the exteriorof the syringe barrel 610. In one or more embodiments, the at least onevent 685 is a formed adjacent the open proximal end 659 of the stopperhub 650 and permit fluid communication after the distal end 641 of theplunger rod 640 moves in the proximal direction past the vent 685. Asshown in FIG. 60, the least one vent 685 is formed on the peripheralwall 653 in the form of two openings adjacent to the open proximal end659 of the stopper hub 650. In one or more alternative embodiments (notshown), the peripheral wall 653 may be free of any vents or openings.

The length of the peripheral wall 653 may be modified to have a lengthand/or cross-sectional width to provide enough volume within the hubcavity 655 to evacuate all of the air present in the chamber 618, tip620 and/or needle cannula 682. In embodiments which do not incorporateat least one vent in the peripheral wall 653, the length of theperipheral wall 653 may be modified to provide enough volume within thehub cavity 655 to maintain all of the air evacuated from the chamber618, tip 620 and/or needle cannula 682.

As mentioned above, the slidable engagement of the stopper hub 650 andthe plunger rod 640 permits the volume of the hub cavity 655 to expandand contract as the plunger rod 640 moves in a proximal direction and adistal direction relative to the stopper hub 650. The expansion of thehub cavity 655 during movement of the plunger rod 640 in a proximaldirection relative to the stopper hub 650 creates a vacuum within thehub cavity 655.

In use, the distal end 641 of the plunger rod 640 is attached to theplunger-engaging portion 656 at the proximal end 659 of the stopper hub650. The plunger rod 640 shown more clearly in FIGS. 56-57 also includesa proximal end 649 and an elongate body 642 extending from the distalend 641 and the proximal end 649. The proximal end 649 of the plungerrod 640 may include an optional thumbpress 648. The plunger rod 640 maybe made of a plastic or other material that has sufficient rigidity towithstand movement within the syringe barrel 610 in the proximal anddistal direction. Examples of such materials include polypropylene,polyethylene, polycarbonate and combinations thereof. The elongate body642 may be cylindrical. In one or more embodiments, the shape of theelongate body 642 may be rectangular or other shape.

The distal end 641 of the plunger rod includes a means for engaging thestopper hub 650. As shown in FIG. 60, the means for engaging the stopperhub 650 includes a disc member 643 disposed perpendicularly to theelongate body 642 of the plunger rod. The disc member 643 extendsradially and, in one or more embodiments, may include a beveled edge 644adjacent to the distal end 641 of the plunger rod. In a specificembodiment, the disc member 643 includes one beveled edge disposed onthe distal side of the disc member and one beveled edge on the oppositeside of the disc member 643. The beveled edge may be formed around theperiphery of the disc member 643. As shown, the disc member 643 has across-sectional width equal that permits the disc member 643 to form afluid-tight seal with the peripheral wall 653 and cooperates with thestop face 658 of the ridge 657 as means for preventing distal movementof the plunger rod 640 with respect to the stopper hub 650. The plungerrod 640 includes a first strut member 645 proximally adjacent to thedisc member 643 disposed between the disc member 643 and a first support646. As shown in FIG. 60, the first strut member 645 may be formed fromtwo perpendicular beams, wherein at least one beam includes at least onebeveled edge on one or both ends of the beam. The first support 646 maybe attached directly to the elongate body 642 of the plunger rod 640 ormay further include a secondary strut member 647 and a second support626 attached to the elongate body 642, as shown in FIG. 60. Thesecondary strut member 647 may be formed from two perpendicular beamshaving elongated support legs 628 for attachment to the second support626, which is disposed distally adjacent to the elongate body 642. Thesecond support 626 may have a cross-sectional width greater than thecross-sectional width of the peripheral wall 653 of the stopper hub 650.

In use, as shown in FIG. 61, the plunger rod 640, stopper hub 650 andstopper 660 are assembled as a medical device 600 and are inserted intothe open proximal end 619 of the syringe barrel 610. The disc member 643of the plunger rod 640 is positioned adjacent to the open distal end 651of the stopper hub 650 and distally adjacent to the stop face 658 of theridge 657, as shown in FIGS. 61 and 62. Before aspirating fluid into thechamber 618 of the syringe barrel 610 or other container, the distalface 672 of the stopper 660 is positioned adjacent to the distal wall612 of the syringe barrel 610, so that the air within the chamber 618 isminimized and is primarily present in the tip 620 of the syringe barrel610 or other container.

In the assembled state, the stopper 660 and stopper hub 650 form aunitary piece that moves together in the distal and proximal directionswithin the chamber 618. The plunger rod 640 and stopper hub 605 areengaged in a slidable relationship where the plunger rod 640 may move inthe proximal and distal direction relative to the stopper hub 650. Thisrelative movement occurs as the stopper hub 650 and stopper 660 toremain stationary with respect to movement of the plunger rod 640.

As shown in FIGS. 61-62, the hub cavity 655 is in an unexpanded statebefore use. To aspirate liquid into the chamber 618, the user mayposition the syringe barrel 610 or other container and needle assembly680 over a vial 50 and insert the needle cannula 684 into the vialbefore applying the initial proximal force to the plunger rod 640, asshown in FIG. 63. To create a vacuum within the hub cavity 655, whichcauses the evacuation of air from the syringe, an initial proximallydirected force is applied to the plunger rod 640, as shown in FIGS.63-64. The expansion of the hub cavity 655 creates a vacuum within thehub cavity 655 that draws the air contained in the tip 620 and chamber618 of the syringe barrel 610 into the hub cavity 655 through theopening 674 of the stopper 660 and the plurality of apertures 694disposed on the porous portion 691 of the filter 690. In one or moreembodiments, the evacuated air may escape from the syringe barrel 610through the at least one vent 685 formed on the peripheral wall 653 tothe exterior of the syringe barrel. In embodiments which do not utilizeany vents in the peripheral wall 653, the air remains within the hubcavity 655 and does not enter the chamber 618 of the syringe barrel 610.

As the air is evacuated from the chamber 618 into the hub cavity 655,some liquid may also be drawn into the chamber 618 of the syringe barrel610 by the vacuum within the hub cavity 655 or by application of acontinuous proximal force on the plunger rod 640, which causes the andattached stopper 660 and stopper hub 650 to move with the plunger rod640 in the proximal direction, as shown in FIG. 65. Once the liquidcontacts the filter 690 and, more specifically, the porous portion 691,the swellable polymer begins to expand and swell, thereby closing theplurality of apertures 694 that allow air to be evacuated from thechamber 618 to the hub cavity 655. When closed, the plurality ofapertures 694 prevents the aspirated liquid from entering the hub cavity655. As the force is applied to the plunger rod 640 in the proximaldirection, the plunger-engaging portion 656 prevents the plunger rod 640from separating from the stopper hub 650.

To expel the fluid, a force in the distal direction is applied to theplunger rod 640 and the plunger rod 640, stopper hub 650 and stopper 660move together in the distal direction. As shown in FIG. 66, the stopface 658 prevents movement of the plunger rod 640 in the distaldirection relative to the stopper hub 650, and maintains the expandedvolume of the hub cavity 655. In embodiments which utilize a flexibledistal face 672, the application of a continuous and distally directedforce on the plunger rod 640 causes the distal face 672 to flex convexlyas the distal face 672 contacts the distal wall 612 of the syringebarrel 610. In embodiments which utilize a stopper 660 having aconvexly-shaped distal face 672, the distal face 672 conforms moreclosely to the distal wall 612 upon contact with the distal wall 612.The convex shape of the distal face 672 upon contact with the distalwall 612 expels even more liquid from the syringe barrel 610.

A medical device 700 according to a seventh aspect of the presentinvention is shown in FIGS. 68-76. The medical device 700 includes atwo-piece plunger rod assembly with a first plunger rod piece 730 and asecond plunger rod piece 750 or a slidable portion that are slidablyengaged to be positioned from a compressed state 797 to an extendedstate 795. The change in position of the first plunger rod piece 730 andthe second plunger rod piece 750 from the compressed state 797 to anextended state 795 creates a vacuum within the plunger rod assembly toevacuate air from a container. The first plunger rod piece 730 includesa sealing edge 745 and a body 732, which may be tubular in shape,extending proximally from the sealing edge 745 defining a plunger rodcavity 734 and the second plunger rod piece 750 is inserted within thebody 732. The second plunger rod piece 750 is disposed within theplunger cavity 734 and includes a sealing portion 765 for forming afluid-tight seal with an inside surface 733 of the body 732.

For illustration, the medical device 700 is shown in use with acontainer in the form a syringe barrel 710. It will be understood thatother types of containers may be utilized with the medical device 700.As shown more clearly in FIGS. 68-69, the syringe barrel 710 includes anopen proximal end 719 and a distal end 711 and a distal wall 712. Asidewall 714 extends from the distal end 711 to the open proximal end719 and includes an interior surface 716 that defines a chamber 718 forretaining or holding fluids, which may include liquid medication and/orother liquids. The distal end 711 may also include a tip 720 having anopen passageway 722 therethrough in fluid communication with the chamber718. The open proximal end of the barrel may include optional flanges724. A needle cannula 784 is attached to the tip 720 and includes alumen 786 or opening therethrough in fluid communication with the openpassageway 722 and the chamber 718. As shown, the needle cannula 784 isattached directly to the tip 720 without the use of a needle hub, usingmethods known in the art. In one or more embodiments, the needle cannula784 may be attached to the tip using a needle hub (not shown). Theinterior surface 716 of the syringe barrel 710 may have a smooth surfacethat is free of any protrusions or depressions. In use, the secondplunger rod piece 750 is inserted into the body 732 of the first plungerrod piece 730, forming the medical device 700, which is then insertedinto the open proximal end 719 of the syringe barrel 710.

As more clearly shown in FIG. 69, the first plunger rod piece 730includes a distal end 731, an open proximal end 739, with the body 732extending from the distal end 731 to the open proximal end 739. Thedistal end 731 includes an opening in fluid communication with theplunger rod cavity 734. In the embodiment shown, the distal end 731includes a distal face 735 and an extension 736 extending in the distaldirection from the distal face. The extension 736 defines a path 738extending from the opening 737 to the inside surface 733 of the body732. The opening 737 and the path 738 are in fluid communication withthe plunger rod cavity 734. The distal face 735 may have a convex shapeor be flexible to flex to a convex shape which conforms to the distalwall 712 of the syringe barrel 710. In one or more embodiments, thedistal face 735 may also be shaped convexly so that it conforms moreclosely to the shape of the distal wall 712 of the syringe barrel 710 toexpel as much liquid from the chamber 718 as possible.

The body 732 may be made of a rigid plastic or other material. Examplesof such materials include polypropylene, polyethylene, polycarbonate andcombinations thereof. The body 732 may be cylindrical. In one or moreembodiments, the shape of the body 732 may be rectangular or othershape.

A portion of the inside surface 733 the body 732 adjacent to the distalface 735 at the distal end 731 of the first plunger rod piece 730 may beshaped to include an enlarged cross-sectional width portion 743 havingan enlarged cross-sectional width for accommodating the sealing portion765 of the second plunger rod piece 750. The second sealing portion 765fits within the enlarged cross-sectional width portion 743 of the firstplunger rod piece 730 as shown in FIG. 71, when the first plunger rodpiece 730 and second plunger rod piece 750 are assembled in thecompressed state 797.

As shown in FIG. 69, the body 732 includes a retainer 744 disposed at apoint along the length of the body 732. As shown in FIGS. 68-76, theretainer 744 includes at least one opening 746 disposed at a distancefrom the open proximal end 739 of the first plunger rod piece 730. Whenassembled with the second plunger rod piece 750, the at least oneopening 746 engages a corresponding structure on the second plunger rodpiece 750, to assemble the medical device 700 in an extended state 795,as shown more clearly in 71-75 and as will be described in additionaldetail below. In one or more embodiments, the retainer 744 may be formedon the inside surface 733 of the body 732 as a groove (not shown) ornotch (not shown) for engaging a corresponding structure on the secondplunger rod piece 750. As shown in FIGS. 68-76, the retainer 744provides visual indication of assembly of the medical device 700 in theextended state 795. The retainer 744 and/or the corresponding structureon the second plunger rod piece 750 may have a shape that providesaudible indication of assembly of the medical device 700 in the extendedstate 795.

The distal end 731 also includes a sealing edge 745 extending radiallyoutwardly and forming a fluid-tight seal with the interior surface 716of the syringe barrel 710. As shown in FIGS. 68-76, the sealing edge 745is formed on the distal end 731 of the body 732 adjacent to the distalface 735 and includes a plunger rod cavity 734 in fluid communicationwith the void. The sealing edge 745 may be formed along the outerperiphery of the distal face 735. Alternatively, the sealing edge 745may be a separate piece and may attach to the distal end 731 of the body732 or, in a specific embodiment, to the peripheral edge of the distalface 735. The sealing edge 745 may be formed form the same material asthe body 732. In a more specific configuration, the sealing edge 745 isformed from an elastomeric material, polymeric material or other knownmaterial suitable for forming a fluid-tight seal with the interiorsurface 716 of the syringe barrel 710. As shown in FIG. 69, the sealingedge 745 may extend distally and form the extension 736 of the body 732and/or the distal face 735 of the first plunger rod piece 730. In one ormore embodiment, the distal end 731 may be free of an extension 736 andmay terminate at the distal face 735.

The distal end 731 of the body includes a porous portion 790. The porousportion 790 as shown in FIG. 69 may be a separate component that isinserted and disposed within the plunger rod cavity 734 and positionedadjacent the distal face 735 and the path 738. In one or moreembodiments, the porous portion 790 is integrally formed on the distalface 735 and may cover the opening 737 such that the extension 736 isdisposed distally adjacent to the porous portion 790 and remainsnon-porous. The porous portion 790 may also be disposed proximallyadjacent the opening 737 and within the path 738. In one or moreembodiments, the porous portion 790 is integrally formed on the distalface 735, with the peripheral edges of the distal face 735 and thesealing edge 745 remaining non-porous. In a specific embodiment, theporous portion 790 is separated from the sealing edge 745 by the distalface 735. In one or more embodiments, the porous portion 790 is formedfrom a hydrophobic filter and/or a swellable polymer, as describedherein. As otherwise described herein, the porous portion 790 is airpermeable and liquid impermeable to permit air to flow from thecontainer or syringe barrel 710 into plunger rod cavity 734 of the body.

As shown in FIGS. 68-69, the porous portion 790 has a circular shape.Alternatively, the porous portion 790 may have a square and/orrectangular shape. In a specific embodiment, the porous portion 790 hasa cross-sectional width that is equal to or larger than thecross-sectional width of the opening 737. In a more specific embodiment,the porous portion 790 has a cross-sectional with that is equal to orsmaller than the cross-sectional width of the inside surface 733 of thebody 732. In an even more specific embodiment, the porous portion 790has a cross-sectional width between the cross-sectional width of theopening 737 and the cross-sectional width of the inside surface 733 ofthe body 732.

The second plunger rod piece 750 includes a distal end 751 and aproximal end 759 and a body or elongate stem 752 extending from thedistal end 751 to the proximal end 759. The elongate stem 752 may bemade of a rigid plastic or other material. Examples of such materialsinclude polypropylene, polyethylene, polycarbonate and combinationsthereof.

The distal end 751 includes a sealing portion 765 that forms afluid-tight seal with the inside surface 733 of the body 732. The secondplunger rod piece 750 is disposed within the plunger rod cavity 734 ofthe body 732 and is moveable in the proximal and distal direction withinthe plunger rod cavity 734 of the body 732. The sealing portion 765 maybe integrally formed on the elongate stem 752 or may be a separate piecethat is attached to the distal end 751 of the second plunger rod piece750. The sealing portion 765 may also be disposed at other locationsalong the elongate stem 752 between the distal end 751 and theengagement portion 760, which will be described below, and is shown inthe embodiments of FIGS. 68-69 as extending radially outwardly from theelongate stem 752 and having a disc-shape. The shape of the sealingportion 765 may be modified to form a fluid-tight seal with a body 732having non-cylindrical shapes. The sealing portion 765 may be formedfrom the same material as the elongate stem 752 or may be formed from adifferent material. In one or more embodiments, the sealing portion 765may be formed from an elastomeric material, polymeric material or othersuitable material for forming a fluid-tight seal with the interiorsurface 716 of the syringe barrel 710.

The proximal end 759 of the second plunger rod piece includes athumbpress 754. The thumbpress 754 has a cross-sectional width that islarger than the cross-sectional width defined by the inside surface 733of the body 732 adjacent to its proximal end 739. In one or moreembodiments, the thumbpress 754 is shaped and/or sized to abut theextension 740, and is prevented from entering the plunger rod cavity 734of the body 732.

The second plunger rod piece 750 includes an engagement portion 760adjacent to the proximal end 769. The engagement portion 760 has astructure to engage the retainer 744 of the body 732 of the firstplunger rod piece 730 so the medical device 700 may be assembled in theextended state 795. The engagement portion 760 shown in FIG. 68-69 is inthe form of two distally extending arms 761, 762. One or both of thearms 761, 762 may include a radially outwardly extending protrusion 763.In one or more embodiments, the engagement portion 760 may include onlya single arm.

As shown, the arms 761, 762 extend in the distal direction from asupport 764 disposed adjacent to the thumbpress 754. The arms 761, 762are positioned in a parallel configuration and form a channel 757 withthe elongate stem 752. As shown more clearly in FIG. 71, the arms 761,762 and are radially inwardly flexible and flex into the channel 766toward the elongate stem 752 upon application of an inwardly-directedradial force. The support 764 is shown in FIGS. 68-69 as integrallyformed on the elongate stem 752, adjacent the proximal end 759 andextending partially along the length of the elongate stem 752. As shownin FIGS. 68-76, the support 764 enlarges the cross-sectional width ofthe elongate stem 752. The length of the support 764 and/or the lengthof the arms 761, 762 may be adjusted to adjust the length of the plungerrod assembly configured or arranged in the extended state 795. Theengagement portion 760 may have an alternate structure that permits theengagement with the retainer 744 of the body 732 of the first plungerrod piece 730. For example, the elongate stem 752 may include one ormore depressible protrusions (not shown) that may be depressed by theinside surface 733 of the body 732 to allow movement of the secondplunger rod piece 750 in the proximal and distal directions within theplunger rod cavity 734 of the body 732. When aligned with the retainer744 of the body 732, the force applied the one or more depressibleprotrusions (not shown) by the inside surface 733 of the body 732 isreleased so the protrusions 763 are no longer depressed and engage theretainer 744.

When the distal end 751 of the second plunger rod piece 750 ispositioned immediately adjacent to the distal face 735 of the firstplunger rod piece 730, the engaging portion 760 and the retainer 744remain unengaged and the medical device 700 is assembled in thecompressed state 797, as shown in FIG. 68. The second plunger rod piece750 is moveable in the proximal and distal directions within the plungerrod cavity 734 of the first plunger rod piece 730 for the distance D1without engagement between the engagement portion 760 or without theengagement of the opening 746 of the retainer 744 and the protrusion 763disposed on one or both arms 761, 762. Movement of the second plungerrod piece 750 in the proximal direction relative to the first plungerrod piece 730 for a distance greater than D1 causes engagement of theengagement portion 760 of the second plunger rod piece 750 and theretainer 744 of the first plunger rod piece 730. This proximal movementof the second plunger rod piece 750 relative to the first plunger rodpiece 730 also creates a vacuum within the plunger rod cavity 734 of thebody as the volume of the plunger rod cavity 734 increases and thesealing portion 765 forms a fluid-tight seal with the inside surface 733of the first plunger rod piece 730, as shown in FIGS. 72-76. The vacuumwithin the plunger rod cavity 734 is maintained once formed due to theprotrusion 763 extending through the retainer 744 and locking the firstplunger rod piece 730 and the second plunger rod piece 750 in theextended state 795. When engaged in the extended state 795, the firstplunger rod piece 730 and the second plunger rod piece 750 are moveableas a unitary structure in the proximal and distal directions within thechamber 718 of the syringe barrel 710.

Prior to use, the medical device 700 is disposed within the chamber 718of the syringe barrel 710 in a compressed state 797, as shown in FIGS.70-71. The distal face 735 is disposed adjacent to the distal wall 712of the syringe barrel 710 so the air within the chamber 718 is minimizedand is primarily present in the tip 720 of the syringe barrel 710 orother container. As shown in FIGS. 70-71, the extension 736 of the body732 is disposed within the passageway 722 of the tip 720 at the distalend 711 of the syringe barrel to further minimize the amount of airwithin the syringe barrel 710. To aspirate liquid into the chamber 718of the syringe barrel 710, the user may position the syringe barrel 710or other container and the needle cannula 784 over a vial 50 and insertthe needle cannula 784 into the vial 50, as shown in FIG. 70.

As shown in FIGS. 72-73, to evacuate the air from the syringe barrel710, the user applies an initial force in the proximal direction to thesecond plunger rod piece 750 while the first plunger rod piece 730remains stationary. The second plunger rod piece 750 moves in theproximal direction for the distance of D1 or until the protrusion 763engages the retainer 744 of the body 732 and the first plunger rod piece730 and the second plunger rod piece 750 are assembled in the extendedstate 795. This movement of the second plunger rod piece 750 relative tothe first plunger rod piece 730 creates a vacuum within the plunger rodcavity 734, which draws air and/or liquid from the vial 50, through theneedle cannula 784 and tip 720 and into the chamber 718 of the syringebarrel 710. The air contained in the tip 720, needle cannula 784 andchamber 718 of the syringe barrel 710 is drawn into the plunger rodcavity 734 of the body 732 through the opening 737, path 738 and porousportion 790.

As the air is evacuated into the plunger rod cavity 734, some liquid maybe drawn into the chamber 718 of the syringe barrel 710 by the vacuumwithin the plunger rod cavity 734 of the body and/or by an applicationof a force on the plunger rod assembly in the proximal direction, whichcauses the first plunger rod piece 730 and second plunger rod piece 750to move in the proximal direction together, while assembled in theextended state 795. The engagement of the retainer 744 and engagementportion 760 prevents the second plunger rod piece 750 from movingindependently in the proximal or distal directions relative to the firstplunger rod piece 730. In addition, the porous portion 790 prevents theaspirated liquid from permeating through the porous portion 790 into theplunger rod cavity 734 of the body 732, as shown in FIGS. 74-75.

As discussed above, the porous portion 790 may include a hydrophobicfilter or a swellable polymer as described herein. In embodiments wherethe porous portion 790 includes a hydrophobic filter, the hydrophobicfilter resists liquid from wicking through the filter at a reasonablepressure gradient. In embodiments which utilize a swellable polymer inthe porous portion 790, the swellable polymer begins to expand andswell, closing any openings that permitted air to permeate through theporous portion 790 from the chamber 718 into the plunger rod cavity 734of the body.

To expel the fluid, a distally directed force is applied to the medicaldevice 700, while it remains assembled in the extended state 795, tomove the medical device 700 in the distal direction. As shown in FIG.76, the engagement of the retainer 744 and the protrusion 763 preventsmovement of the second plunger rod piece 750 in the distal directionrelative to the first plunger rod piece 730, regardless of whether theuser applies pressure to the thumbpress 754 of the second plunger rodpiece 750 or the extension 740 of the first plunger rod piece 730. Thevolume of the plunger rod cavity 734 remains the expanded or enlargedafter the initial proximal movement of the second plunger rod piece 750relative to the first plunger rod piece 730 as the desired amount ofliquid is expelled from the chamber 718 of the syringe barrel 710.

In one or more embodiments that utilize a first plunger rod piece 730having a distal face 735 that flexes, the application of a continuousand distally directed force on the first plunger rod piece 730 and thesecond plunger rod piece 750 causes the distal face 735 to flex convexlyas the distal face 735 contacts the distal wall 712 of the syringebarrel 710. In embodiments which utilize a first plunger rod piece 730having a convexly-shaped distal face 735, the distal face 735 conformsmore closely to the distal wall 712 upon contact with the distal wall712. Upon contact with the distal wall 712, the convex shape of thedistal face 735 expels even more liquid from the syringe barrel 710.

FIGS. 77-85 illustrate a medical device 800 according to an eighthaspect of the present invention. The medical device 800 includes aplunger rod and stopper assembly having a pre-formed vacuum and a needlesupported on a container to pierce the vacuum to evacuate air from thecontainer. In one or more embodiments, the medical device 800 may beutilized with a container, for example, a syringe barrel 810. As shownmore clearly in FIG. 84, the syringe barrel 810 includes an openproximal end 819, a distal end 811 and a distal wall 812. A sidewall 814extends from the distal end 811 to the open proximal end 819 andincludes an interior surface 816 that defines a chamber 818 forretaining or holding fluids, which may include liquid medication and/orother liquids. The distal end 811 may also include a tip 820 having anopen passageway 822 therethrough in fluid communication with the chamber818. As shown, the distal end 811 of the syringe barrel 810 includes anoptional luer fitting 826 and the open proximal end 819 of the barrelmay include a flange 824. The needle 880 is shown attached directly tothe tip 820, however, in one or more embodiments, a needle hub (notshown) may be utilized to attach the needle 880 to the tip 820. Theinterior surface 816 of the syringe barrel 810 may have a smooth surfacethat is free of any protrusions or depressions. In use, the plunger rod840 and stopper 860 are inserted into the open proximal end 819 of thesyringe barrel 810 a needle 880 is attached to the tip 820 in fluidcommunication with the chamber 818.

As more clearly shown in FIGS. 77-78, the stopper 860 includes a distalend 861, an open proximal end 869 and a body 862 extending from thedistal end 861 to the open proximal end 869. The body 862 includes aninside surface 864 defining a cavity 866. In one or more embodiments,the inside surface 864 of the body 862 may include a peripheral groove868 forming a channel or ridge within the body 862 for engagement withthe plunger rod 840, as will be described in detail below. As shown inFIGS. 77-85, the body 862 includes an outside surface 863 including asealing portion 870. As shown, the sealing portion 870 is disposedadjacent the distal end 861 for forming a fluid-tight seal with theinside surface 816 of a syringe barrel 810. The stopper 860 may beformed from an elastomeric material, polymeric material or othermaterial known in the art. The sealing portion 870 may have a circularcross-section for forming a fluid-tight seal with a syringe barrel 810having an inside surface 816 with a circular cross-section. The shape ofthe sealing portion 870 may be modified to form a fluid-tight seal withsyringe barrels having different cross-sectional shapes. The sealingportion 870 may be formed from any material suitable for forming afluid-tight seal with the interior surface 816 of the syringe barrel810, which may be the same or different material utilized to form thestopper 860.

The distal end 861 of the stopper 860 includes a pierceable distal face872 or pierceable septum that forms a pierceable seal with the stoppercavity 866 and seals a vacuum formed within the plunger rod 840 when theopen proximal end 869 of the stopper 860 is attached to the plunger rod840. The vacuum within the plunger rod 840 may be formed prior toattachment of the stopper 860 and plunger rod 840 using means known inthe art. For example, the plunger rod 840 may include an open distal endin fluid communication with the cavity 866 and an interior plunger (notshown) disposed telescopically within the plunger rod 840 and forming afluid tight seal with the inside surface of the plunger rod 840. Theinterior plunger (not shown) may be partially withdrawn from the plungerrod 840 to create a vacuum within the plunger rod 840 and the cavity866, as described with reference to the embodiments according to theseventh aspect of the present invention. Alternatively, the vacuum maybe preformed within the plunger rod 840, during assembly with thestopper 860. The pierceable distal face 872 may have a convex shape orbe flexible to flex to a convex shape which conforms to the distal wall812 of the syringe barrel 810. In one or more embodiments, the distalface 872 may also be shaped convexly so that it conforms more closely tothe shape of the distal wall 812 of the syringe barrel 810 to expel asmuch liquid from the chamber 818 as possible. The pierceable distal face872 may be formed from an elastomeric material and may have a uniformthickness or a varying thickness. In one or more specific embodiments,the thickness of the pierceable distal face 872 may be varied tofacilitate piercing by the needle 880.

As discussed above, the plunger rod 840 is attached to the open proximalend 869 of the stopper. The plunger rod 840 shown more clearly in FIGS.77 and 80 includes an open distal end 841, a proximal end 849, and ahollow body 842 extending from the open distal end 841 and the proximalend 849. The hollow body 842 includes an interior surface 843 thatdefines a void 844. As discussed above, in one or more embodiments, thevoid 844 of the plunger rod 840 includes a vacuum. The vacuum may alsobe present within the stopper cavity 866 when the plunger rod 840 isassembled with the stopper 860. In one or more alternative embodiments,the open distal end 841 of the plunger rod may be covered and sealed bya pierceable wall (not shown) that is air and liquid impermeable tomaintain the vacuum within the void 844 prior to release by the needle880, as will be described in more detail below. The plunger rod 840 maybe made of a rigid plastic or other material that has a greater rigiditythan the stopper 860. Examples of such materials include polypropylene,polyethylene, polycarbonate and combinations thereof. The hollow body842 may be cylindrical. In one or more embodiments, the shape of thehollow body 842 may be rectangular or other shape. The proximal end 849of the plunger rod 840 includes an optional thumbpress 848.

The open distal end 841 of the plunger rod includes stopper-engagingportion 850 having a distal end 851 and a proximal end 859. Thestopper-engaging portion 850 includes a sidewall support 852 extendingfrom the proximal end 859 to the distal end 851 of the stopper-engagingportion 850. As shown in FIG. 78, a disc 853 extends radially outwardlyfrom the distal end 851 of the sidewall support 852. Specifically, asmore clearly shown in FIG. 78, the disc 853 extends radially outwardlyto engage the peripheral groove 868 of the stopper 860. Thestopper-engaging portion 850 may include a tab (not shown), whichcorresponds to an opening or other corresponding structure on the insidesurface 864 of the stopper. In a specific embodiment, thestopper-engaging portion 850 may have an opening (not shown) and theinside surface 864 of the stopper 860 may include a tab (not shown)extending radially inwardly to engage with the opening (not shown) ofthe stopper 860. Other means to engage the plunger rod 840 to thestopper 860 may also be utilized. Alternatively, the stopper 860 may beintegrally formed on the distal end 841 of the plunger rod 840.

A first porous portion 830 is disposed within the sidewall support 852.As shown, the sidewall support 852 defines a hollow interior 854 havinga cross-sectional width greater than the cross-sectional width definedby the interior surface 843 of the plunger rod. The hollow body 842 ofthe plunger rod forms a ledge 855 for supporting the first porousportion 830 within the hollow interior 854 of the sidewall support 852.The first porous portion 830 shown in FIG. 78 includes an open distalend 831 and a proximal end 839 permitting fluid communication betweenthe hollow interior 854 and the cavity 866 of the stopper 860. In theembodiment shown in FIGS. 77-85, the first porous portion 830 includesan outside wall 832 extending from the distal end 831 to the proximalend 839, a bottom support 836 at the proximal end 839. The first porousportion 830 may be formed from hydrophobic filter, a swellable polymerand combinations thereof, as described herein. When the first porousportion 830 includes a swellable polymer, the openings present in theswellable polymer close upon contact with the liquid. In embodimentswhich include a first porous portion 830 formed from a hydrophobicfilter or membrane, the hydrophobic filter prevents liquid frompermeating through the first porous portion 830 and entering the plungerrod 840. As shown, the bottom support 836 forms a liquid impermeablebarrier between the cavity 866 of the stopper 860 and the void 844 ofthe plunger rod 840.

In the embodiment shown, the first porous portion 830 is shaped tosupport a second porous portion 890. In one or more embodiments, themedical device 800 includes only a first porous portion 830 and nosecond porous portion 890. In one or more alternative embodiments, themedical device 800 includes only a second porous portion 890 and nofirst porous portion 830. In a more specific embodiment, the firstporous portion 830 may be replaced by a pierceable wall (not shown) toseal the vacuum within the void 844 of the plunger rod.

In the embodiment shown in FIGS. 77-85, the outside wall 832 and bottomsupport 836 form a space 835 in fluid communication with the stoppercavity 866 and forms a partial enclosure for the second porous portion890, which is also in fluid communication with the cavity 866.

The second porous portion 890 disposed within the space 835 of the firstporous portion 830 is air permeable and liquid impermeable. In one ormore embodiments, the second porous portion 890 may include ahydrophobic filter or a swellable polymer as described herein.Alternatively, the second porous portion 890 may be composed of aplurality of hydrophobic papers.

The second porous portion 890 may be shaped to fit within the space 835.As shown, the second porous portion 890 is shown as a ring-shaped memberhaving a hollow interior 892. In one or more embodiments, the secondporous portion 890 may be disc-shaped or other shape to occupy the space835. In one or more embodiments, the second porous portion 890 has acircular shape having an opening. In one or more embodiments, the secondporous portion 890 is integrally formed within the space 835, bottomsupport 836 and outside wall 832 of the first porous portion 830.Alternatively, the second porous portion 890 may be disposed along theinside surface 864 of the stopper 860 at the distal face or across theopen distal end 841 of the plunger rod.

The needle 880 is attached to the tip 820 of the syringe barrel 810 andextends partially into the chamber 818 of the syringe barrel. As moreclearly shown in FIG. 79, the needle 880 includes an open distal end881, an open proximal end 889 and a cannula 882 extending from thedistal end 881 to the proximal end 889. The open proximal end 889includes a beveled edge 885 forming a piercing point 884 for piercingthe distal face 872 of the stopper. In one or more embodiments, the opendistal end 881 may optionally include a beveled and/or blunt edge. Thecannula 882 includes a vent 886 disposed adjacent to the open proximalend 889 of the needle. As shown in FIG. 81, the vent 886 is completelyenclosed and may be in the shape of a circular opening.

In use, as shown in FIG. 80, the plunger rod 840 and stopper 860 areassembled as a medical device 800 and are inserted into the openproximal end 819 of the syringe barrel 810. Before aspirating fluid intothe chamber 818 of the syringe barrel 810, the stopper 860 and plungerrod 840 are positioned so that the vacuum within the plunger rod 840 ismaintained, while minimizing the air within the syringe barrel 810. Inone or more embodiments, the vacuum is present within the plunger rod840 and stopper 860 assembly and the pierceable distal face 872 isdisposed at a minimal distance from the piercing point 884 to maintainthe vacuum within the plunger rod 840 and stopper 860 assembly. In oneor more embodiments, the pierceable distal face 872 may be positionedadjacent to the piercing point 884 of the needle 880. In a more specificembodiment, the piercing point 884 may partially penetrate thepierceable distal face 872, while the pierceable distal face 872 remainsintact. In embodiments which utilize a plunger rod 840 including apierceable wall (not shown) that covers the open distal end 841 of theplunger rod to seal the vacuum within the void 844, the needle 880 maybe disposed such that it extends farther into the chamber 818 and intothe stopper cavity 866 to a position that a minimal distance from thepierceable wall (not shown) so the vacuum within the void 844 ismaintained.

As shown in FIGS. 81 and 82, to fill the chamber 818 of the syringebarrel 810, the distal end 881 of the needle 880 is inserted into acontainer, such as a vial 50. In the embodiment shown in FIGS. 81-82,after the needle 880 is inserted into the vial, the air is trappedbetween the liquid within the needle 880 and the pierceable distal faceof the stopper. There is also air present in the chamber 818 between thestopper 860 and the distal wall 812 of the syringe barrel 810.Thereafter, an initial force in the distal direction is applied to theplunger rod 840 so the piercing point 884 pierces and penetrates throughthe pierceable distal face 872 to release the vacuum contained withinthe cavity 866 of the stopper 860 and the void 844 of the plunger rod840. In embodiments that utilize a pierceable wall (not shown) tomaintain a vacuum within the void 844 of the plunger rod, the piercingpoint 884 pierces the pierceable wall (not shown) to release the vacuum.

As the vacuum is released by the piercing point, the vacuum draws airfrom the chamber 818 and the needle 880 into the cannula 882 into thecavity 866 of the stopper. As the air is evacuated into the cavity 866,some liquid may be drawn into the cavity 866 of the stopper 860 by thevacuum within the plunger rod 840. The first porous portion 830 and/orthe second porous portion 890 of the stopper 860 prevent liquid fromentering the void 844 of the plunger rod 840. For example, inembodiments which utilize a first porous portion 830 and/or secondporous portion 890 that includes a swellable polymer, the openingspresent in the swellable polymer close upon contact with the liquid. Inembodiments which utilize a first porous portion 830 and/or secondporous portion 890 including a hydrophobic filter or membrane, thehydrophobic filter prevents liquid from permeating through the porousportion.

As shown in FIG. 84, the desired amount of liquid may be filled into thesyringe barrel 810, without the presence of air. During aspiration, theneedle 880 remains stationary and the user continues to apply a force onthe thumbpress 848 in the proximal direction and the plunger rod 840 andstopper 860 move in the proximal direction. The hole or opening createdin the pierceable distal face 872 by the piercing point 884 of theneedle 880 reseals, providing a fluid tight seal or barrier to theliquid between the cavity 866 and the chamber 818. In other words, thepierceable distal face 872 forms a seal between the chamber 818 and thecavity 866 of the stopper 860 after the stopper 860 and plunger rod 840move in the proximal direction away from the piercing point 884.

To expel the fluid, the user applies a force on the plunger rod 840 orthumbpress 848 in the distal direction, causing the stopper 860 andplunger rod to move in the distal direction as shown in FIG. 85. In oneor more embodiments that utilize a stopper 860 having a distal face 872that flexes, the application of a continuous and distally directed forceon the plunger rod 840 causes the distal face 872 to flex convexly asthe distal face 872 contacts the distal wall 812 of the syringe barrel810. In embodiments which utilize a stopper 860 having a convexly-shapeddistal face 872, the distal face 872 conforms more closely to the distalwall 812 upon contact with the distal wall 812. The convex shape of thedistal face 872 upon contact with the distal wall 812 expels even moreliquid from the syringe barrel 810.

A ninth aspect of the present invention pertains to a method ofaspirating a container using the various embodiments of medical devicesdescribed in this application. For illustration purposes, reference willbe made to FIGS. 1-85. In one embodiment, the method for aspirating asyringe barrel or other container includes providing a needle cannulaincluding a lumen or opening on the tip of the syringe barrel, insertinga plunger rod assembly having a sealing means within the syringe barreland providing a vacuum within the plunger assembly. In one or moreembodiments, the vacuum is provided by providing a plunger rod assemblywith an expanding cavity. The method may include positioning the stopperimmediately adjacent the distal wall of the syringe barrel to isolate anair source in the open passageway of the tip, submerging the opening orlumen of the needle cannula in a liquid, and drawing air and liquid intothe syringe barrel and evacuating the air or air source from the liquidwithin the syringe barrel. The vacuum may be provided within the plungerrod assembly before or after submerging the opening of the needlecannula in a liquid. In one or more embodiments, the method may includeapplying a force in the distal direction to the plunger rod to causedistal face to flex convexly to minimize the air present in the chamber.In one or more embodiments, the method includes drawing the liquid intothe syringe barrel by applying a continuous force to the plunger rod inthe proximal direction so that the plunger rod and stopper move in theproximal direction together. The method of aspirating may also includethe step of venting the air from the syringe barrel.

In one variant, separating air from the liquid includes forming a vacuumwithin the stopper and providing a distal face on the stopper, anopening in fluid communication with a cavity in the stopper and an airpermeable and liquid impermeable filter between the opening and thecavity. In one or more embodiments, forming a vacuum includes expandingthe volume of the stopper and/or plunger rod. The formation of a vacuumwithin the stopper draws air and liquid into the cavity. The filterpermits air to enter the cavity and prevents liquid from entering thecavity.

Separating air from the liquid may include providing a pre-formed vacuumwithin the plunger rod, providing a distal face on the stopper, anopening in fluid communication with a cavity in the stopper and an airpermeable and liquid impermeable filter between the opening and thecavity and providing a release means to release the vacuum in theplunger rod. In a specific embodiment, the method includes providing arelease means on the stopper that pierces a pierceable barrier on theplunger rod. The release of the vacuum and attachment of the stopper andplunger rod draws air and liquid into the cavity of the stopper. Thefilter permits air to enter the cavity and prevents liquid from enteringthe cavity.

Alternatively, separating air from the liquid includes providing apre-formed vacuum within the stopper, providing a pierceable distal faceon the stopper and an air permeable and liquid impermeable filter withinthe stopper and/or plunger assembly and a release means attached to thecontainer to pierce the pierceable distal face and to release thevacuum. The release of the vacuum draws air and liquid into the cavityof the stopper. The filter permits air to enter the cavity and preventsliquid from entering the cavity.

Separating the air from the liquid may include forming a vacuum withinthe chamber between the plunger rod and the stopper. In a specificembodiment, forming a vacuum within the chamber between the plunger rodand the stopper includes providing a sealing means on the plunger rodfor forming a fluid tight seal with the syringe barrel and a distal faceon the stopper, an opening in fluid communication with a cavity in thestopper including an air permeable and liquid impermeable filter betweenthe opening and the cavity, providing a sealing means on the stopper forforming a fluid tight seal with the syringe barrel and applying an forceto the plunger rod in the proximal direction to expand the distancebetween the stopper and the plunger rod. The formation of a vacuumwithin the stopper draws air and liquid into the cavity. The filterpermits air to enter the cavity and prevents liquid from entering thecavity.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe invention. Thus, the appearances of the phrases such as “in one ormore embodiments,” “in certain embodiments,” “in one embodiment” or “inan embodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the invention.Furthermore, the particular features, structures, materials, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present invention without departing from the spirit andscope of the invention. Thus, it is intended that the present inventioninclude modifications and variations that are within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A medical device comprising: a syringe barrelincluding a side wall having an inside surface defining a chamber forretaining fluid, an open proximal end and a distal end including adistal wall with a tip extending distally therefrom having an openpassageway in fluid communication with said chamber; a plunger rodcomprising a proximal end, a distal end and a body extending from theproximal end to the distal end, the plunger rod disposed within thechamber and moveable in the proximal and distal direction within thechamber, wherein the distal end of the plunger rod includes a taperedneck shaped to form a releasable seal with the opening and the openingincludes an undercut that is shaped to receive the tapered neck of theplunger rod; a stopper assembly disposed within the chamber and moveablein the proximal and distal direction within the chamber, the stopperassembly forming a fluid-tight seal with the inside surface of thesyringe barrel, a stopper including a distal face, a proximal end, anexpandable portion adjacent to the proximal end comprising a bendablewall formed from an elastomeric material having a spring constant thatexpands a stopper cavity to create a vacuum within the stopper cavity,and a body extending from the distal face to the proximal end definingthe stopper cavity, wherein the stopper is attached to the distal end ofthe plunger rod and the proximal end of the stopper includes an openingin fluid communication with the stopper cavity, wherein the distal endof the plunger rod is disposed within the stopper cavity and forms areleasable seal with the opening and is proximally and distally moveablewithin the stopper cavity; and a porous portion associated with thestopper to permit air to flow into the stopper cavity and to preventliquid from entering the stopper cavity, the plunger rod and stopperconfigured to create a pressure differential between the stopper cavityand a portion of the chamber extending from the distal wall and thedistal face of the stopper assembly, wherein the porous portioncomprises a selective barrier that defines a liquid penetration pressureand an air penetration pressure that is less than the liquid penetrationpressure.
 2. The medical device of claim 1, further comprising a ventassociated with the stopper to release the air from the stopper cavity.3. The medical device of claim 1, wherein the porous portion comprisesone of a hydrophilic filter, hydrophobic filter, a swellable polymer ora combination thereof.
 4. The medical device of claim 1, wherein aninitial movement of the plunger rod in a proximal direction relative tothe stopper forms the releasable seal between the distal end of theplunger rod and the opening, and the expandable portion expands anddraws air from the chamber into the stopper cavity through the porousportion disposed between the distal face and the stopper cavity.
 5. Themedical device of claim 4, wherein upon movement of the plunger rod in adistal direction relative to the stopper subsequent to the initialmovement in the proximal direction, the releasable seal is released,allowing the air within the stopper cavity to escape through the openingof the stopper.
 6. The medical device of claim 5, wherein the expandableportion is configured so that upon a continuous movement of the plungerrod relative to the stopper in a distal direction, the distal end of theplunger rod blocks the porous portion and prevents air from exiting thestopper cavity through the porous portion.
 7. The medical device ofclaim 1, wherein the stopper further comprises a sealing portiondisposed between the distal face and the expandable portion forming afluid-tight seal with the inside surface of the syringe barrel, theexpandable portion configured so that upon an initial movement of theplunger rod in a proximal direction, the sealing portion remainsstationary and the expandable portion expands to draw air into thestopper cavity through the porous portion.
 8. The medical device ofclaim 7, wherein the elastomeric material permits expansion of thebendable wall.
 9. The medical device of claim 1, wherein the distal faceis flexible and flexes concavely during movement of the plunger rod in aproximal direction and flexes convexly during movement of the plungerrod in the distal direction.
 10. The medical device of claim 1, whereinthe distal face is convexly shaped and conforms to the distal wall ofthe barrel.
 11. The medical device of claim 1, wherein the expandableportion comprises a pump body having a distal end attached to theproximal end of the stopper and a proximal end defining aplunger-engaging portion attached to the proximal end of the plungerrod, the pump body including a wall that defines a pump cavity in fluidcommunication with the stopper cavity.
 12. The medical device of claim11, wherein the pump body is configured so that upon application of aninitial force on the plunger rod in the distal direction relative to thestopper causes the pump body to compress and a release of the initialforce on the plunger rod in the distal direction allows the pump body toexpand and draw air from the chamber into the stopper cavity through theporous portion disposed between the distal face and the stopper cavity.13. The medical device of claim 12, wherein the stopper furthercomprises a sealing portion disposed between the distal face and theexpandable portion forming a fluid-tight seal with the inside surface ofthe syringe barrel, wherein the sealing portion remains stationary asthe pump body expands.
 14. The medical device of claim 11 wherein thewall comprises a corrugated wall formed from an elastomeric material andhas a spring constant that permits expansion of the corrugated wall. 15.The medical device of claim 1, further comprising a first protrusionpositioned distally adjacent the tapered neck, a boss member distallyadjacent the first protrusion and a second protrusion distally adjacentthe boss member.
 16. The medical device of claim 15, wherein the firstprotrusion has a cross-sectional width to prevent separation of theplunger rod from the stopper.
 17. The medical device of claim 15,wherein the second protrusion includes a perpendicular face having across-sectional width equal to or greater than a cross-sectional widthof the porous portion.
 18. The medical device of claim 15, wherein theboss member has a length that permits movement of the plunger rodwithout separation of the plunger rod from the stopper.
 19. The medicaldevice of claim 15, wherein the tapered neck has a cross-sectional widththat increases from the body of the plunger rod to the first protrusion.20. The medical device of claim 15, wherein the tapered neck has across-sectional width that increases at an angle identical to an angleof the undercut of the stopper.
 21. The medical device of claim 1,wherein the tapered neck is contoured so that at least one portion ofthe tapered neck forms a fluid-tight engagement with the undercut as theplunger rod and stopper move in a proximal direction.